Formation of International Law (147-202)

472. Cf. Chaps. VII-XI, infra.473. G. Scelle, “Essai sur les sources formelles du droit international”, in

Recueil d’études sur les sources du droit en l’honneur de F. Gény, Vol. III, Paris,Rec. Sirey, 1934, pp. 400-430 ; M. Sørensen, Les sources du droit international,Copenhagen, E. Munksgaard, 1946, pp. 13-14.

474. M. Sørensen, op. cit. supra footnote 473, p. 15.

PART III

FORMATION OF INTERNATIONAL LAW

CHAPTER V

CONTEMPORARY INTERNATIONAL LAW-MAKING:A REASSESSMENT OF THE THEORY OF FORMAL “SOURCES”

OF INTERNATIONAL LAW

I. Introduction

The ways and means whereby International Law nowadays mani-fests itself surely do not exhaust themselves in the consideration ofits formal “sources”. The growing complexity of the process of forma-tion of contemporary International Law is a challenge to its scholar-ship, nowadays perhaps to a greater extent than in the past. This isa basic issue which cannot be dissociated, for example, from that ofthe expansion of international legal personality in InternationalLaw 472. Classic doctrine already tended to single out the distinctionbetween formal “sources” of International Law, that is, the meanswhereby this latter manifests itself and its norms are created (cus-tom, treaties, general principles of law, case-law, doctrine, equity,among others), and its so-called material “source”, that is, the sub-stratum — metajuridical — wherefrom the former are originated 473.In fact, the material “source” referred to is, in its turn, ineluctablylinked, ultimately, to the question of the validity itself of the normsof International Law.

This question, however, transcends the ambit of positive law 474.As international lawyers, in their great majority, did not appear pre-pared to enter into this line of enquiry, it became commonplace,somewhat easier, through the years — as attested by numerous books

147

475. Apart from small variations of phraseology (in the introductory phrase)and in the numbering of paragraphs and subparagraphs : cf. Bin Cheng, op. cit.infra footnote 523, pp. 2 and 21.

476. The Advisory Committee was composed of Adatci, Altamira, ClovisBevilaqua (subsequently replaced by Raul Fernandes), Baron Descamps,Hagerup, Albert de La Pradelle, Loder, Lord Phillimore, Ricci-Busatti, ElihuRoot (assisted by J. B. Scott), with D. Anzilotti its Secretary-General ; cit. in BinCheng, op. cit. infra footnote 523, p. 6 n. 19.

477. Including treaties, custom, general principles of law, case-law.478. Cf. proceedings in Cour permanente de Justice internationale/Comité

consultatif de juristes, Procès-verbaux des séances du Comité (16 juin/24 juillet1920) avec Annexes, La Haye, ed. Van Langenhuysen Frères, 1920, pp. 247,270, 293-297, 306-321, 331-339, 344-346, 351, 584, 620 and 729-730. And, fora study of these procès-verbaux, cf. Maarten Bos, “The RecognizedManifestations of International Law — A New Theory of ‘Sources’ ”, 20German Yearbook of International Law (1977), pp. 18 and 33-39.

and courses dedicated to the matter — reiteratedly to circumscribethe study of the matter to the provision of Article 38 of the Statute ofthe International Court of Justice (ICJ), virtually the same as the cor-responding Article of the Statute of the previous Permanent Court ofInternational Justice (PCIJ) 475. The list set forth in that well-knownprovision, however, refers only to the formal “sources”. The study ofthe formation of International Law, in this way, does not — couldnot — exhaust itself in the consideration only of the aforementionedlist of formal “sources”.

II. General Considerations on the Formal “Sources”of International Law

Article 38 of the Statute of the PCIJ and the ICJ provides that, inthe settlement of disputes submitted to it, the Court will apply inter-national conventions, international custom and general principles oflaw, to which are added, as “subsidiary means”, judicial decisionsand doctrine ; the Court is, at last, entitled to decide a question exaequo et bono, “if the parties agree thereto”. The legislative historyof that provision goes back to 1920, when an Advisory Committeeof Jurists was appointed by the Council of the League of Nations 476

to prepare the project for the establishment of a PCIJ.The Committee convened at The Hague from 16 June to 24 July

1920. Draft Article 38 of the PCIJ Statute resulted from a projectoriginally presented by Baron Descamps 477, which was the object ofdebates among the members of the Committee referred to, in whicha decisive influence was exerted, besides the author of the afore-mentioned project, also by E. Root and Lord Phillimore 478. Article 38

148 A. A. Cançado Trindade

479. In 1934, G. Scelle, e.g., criticized the formulation of Article 38 of thePCIJ Statute for have been much influenced by considerations of political order,representing a compromis between the demands of legal technique and the pos-sibilities of intergovernmental relations ; G. Scelle, op. cit. supra footnote 473,p. 411.

480. Ibid., p. 420. 481. M. Sørensen, Les sources . . ., op. cit. supra footnote 473, pp. 28-33.482. Rigorously, doubts were to be raised mainly in respect of treaties, cus-

tom and general principles of law, since Article 38 itself was to characterizecase-law and doctrine as “subsidiary means” and to attribute a limited functionto equity.

483. A. Truyol y Serra, Noções Fundamentais de Direito InternacionalPúblico, Coimbra, A. Amado Ed., 1962, pp. 141-143.

484. Former Soviet authors came even to refuse to recognize any sources ofInternational Law other than treaties and custom ; cf. M. Akehurst, “TheHierarchy of the Sources of International Law”, 47 British Year Book ofInternational Law (BYBIL) (1974-1975), pp. 273-285. Among them, there werethose to whom treaties would prevail over custormary law for being based onthe express agreement of States ; cf. R. R. Baxter, op. cit. infra footnote 485,pp. 101-102.

of the Statute of the old PCIJ (reincorporated two and a half decadeslater also into the Statute of the successor ICJ) soon became theobject of attention for enumerating the “sources” of InternationalLaw, but did not escape criticisms in the years following its adop-tion 479. G. Scelle, for example, observed in 1934 that the very con-ception of the aforementioned Article 38 appeared insufficient tofulfil the social needs that should be taken into account by theInternational Law of the epoch 480. It is to be kept in mind thatArticle 38, however, was never intended to constitute a mandatoryand exhaustive formulation of the “sources” of International Law,but only a guide to the judicial operation of the Hague Court 481.

The provision at issue became also the object of controversy inexpert writing as to the question whether it established or not a hier-archy of sources of Public International Law 482. For the supporters ofthe natural law foundations of International Law, it became less diffi-cult to apprehend the relationship between the general principlesof law, treaties and custom : to them, treaties and custom would be“positivizations” of the general principles of law adapted to thevarying historical situations 483. But this was just one of the existingconceptions. What soon seemed beyond doubt was that theso-called “sources” of International Law appeared in constant anddynamic interaction.

Another point which became constantly clearer pertained to theprominent position of treaties and custom — normally endowed withequal authority — among the sources of International Law 484. There

General Course on Public International Law 149

485. R. R. Baxter, “Treaties and Custom”, 129 RCADI (1970), pp. 31-104 ;A. D. McNair, “Treaties Producing Effects ‘Erga Omnes’ ”, in Scritti di DirittoInternazionale in Onore di T. Perassi, Vol. II, Milan, Giuffrè, 1957, pp. 23-36.

486. Ph. Cahier, “Le problème des effets des traités à l’égard des Etats tiers”,143 RCADI (1974), pp. 589-736. And for a criticism of the preponderant role oftreaties and custom, cf. C. Sepúlveda, Las Fuentes del Derecho InternacionalAmericano, Mexico, ed. Porrúa, 1975, pp. 43-69, and pp. 94-95, on the impor-tance of resolutions of international Conferences. Cf. also comments byM. Panebianco, “La Teoria delle Fonti del Diritto Internazionale nei Fondatoridella Dottrina Latino-Americana (Sec. 18-19)”, in Studi in Onore di G. Sperduti,Milan, Giuffrè, 1984, pp. 163-186 ; J. C. Puig, Les principes du droit interna-tional public américain, Paris, Pedone, 1954, pp. 1-81.

487. Treaties may also serve as evidence of customary law : for example, con-sular bilateral treaties much influenced the development of customary interna-tional law on consular relations, later codified in the 1963 Vienna Convention onConsular Relations ; R. R. Baxter, op. cit. supra footnote 485, pp. 87-89 and101, and cf. p. 98.

488. Cf. examples cit. in, e.g., R. R. Baxter, op. cit. supra footnote 485, pp. 36-37 ; Ch. Schreuer, “Recommendations and the Traditional Sources of InternationalLaw”, 20 German Yearbook of International Law (GYIL) (1977), pp. 113-114.

was support for the view that international custom can be found intreaties, just as treaties can, with the passing of time, move on tocustomary International Law, and even exert effects, qua evidence ofcustomary International Law, on States not parties thereto 485. Withthe exception of this last point, which has been challenged 486, itcame to be admitted nowadays that a treaty may overcome a pre-existing custom (leading to the formation of a new custom), just as asubsequent custom may overcome a treaty 487.

Moreover, the enumeration of “sources” of International Lawlisted in Article 38 of the ICJ Statute was never meant to be, norcould it be, exhaustive. This was soon indicated by decisions of theICJ itself, on the basis of a combination of distinct “sources”, inaddition to other evidences, of International Law 488. It may thus beinferred that the formal “sources” of International Law are not staticcategories, but are rather in constant and dynamic interaction,reflecting, in a non-exhaustive manner, the ways and means ofmanifestation of International Law in time.

III. The Formal “Sources” Enumerated in Article 38of the ICJ Statute

1. International custom

Article 38 itself of the ICJ Statute duly qualifies international cus-tom in referring to it as “evidence of a general practice accepted as


489. Cf. docs. reproduced in K. Marek, Répertoire des décisions et des docu-ments de la procédure écrite et orale de la Cour permanente de Justice interna-tionale et de la Cour internationale de Justice, Vol. 2 : Les sources du droitinternational, Geneva, IUHEI, 1967, pp. 801-831 ; in his Dissenting Opinion inthe case (wherein the PCIJ stressed the “will” of States in the formation of inter-national rules), Judge Nyholm argued that, in the formation of custom, it was bythe continuing repetition of certain acts that an international juridical consciencebegan to manifest itself. Subsequently the PCIC began to move away from itsvoluntarist-positivist thinking, and its successor, the ICJ, dissociated itselffrom it.

490. And his followers of the school of the “pure theory of law”.491. P. Guggenheim, “Les deux éléments de la coutume en droit interna-

tional”, in La technique et les principes du droit public — Etudes en l’honneurde G. Scelle, Vol. I, Paris, LGDJ, 1950, pp. 275-284.

492. A. A. D’Amato, The Concept of Custom in International Law, Ithaca,Cornell University Press, 1971, pp. 242 n. 28, and 74, and cf. pp. 271-272 (forthe “claim-oriented approach”) ; and cf. also J. L. Kunz, “The Nature ofCustomary International Law”, 47 American Journal of International Law(AJIL) (1953), p. 665 ; D. W. Greig, International Law, 2nd ed., London,Butterworths, 1976, p. 19.

493. Sienho Yee, “The News that Opinio Juris ‘Is Not a Necessary Elementof Customary [International] Law’ Is Greatly Exaggerated”, 43 GYIL (2000),pp. 231, 234 and 236-238.

law”. Hence the two classic constitutive elements of custom (consid-ered by the PCIJ as early as in 1927, in the Lotus (France v. Turkey)case 489 : the objective element, represented by the international prac-tice itself, and the subjective element, the opinio juris sive necessi-tatis, i.e., the belief that such practice is in accordance with law andaccepted as such ; this configuration of international custom remainspredominantly accepted to date. Yet, it was once the object of criti-cism on the part of H. Kelsen 490, endorsed by P. Guggenheim, in thesense that the objective element would be sufficient to create customas “source” of law, since the subjective element of the opinio juriswould, in their view, be of difficult determination 491.

In counterposition to this outlook, many other authors considerednecessary or useful the preservation of the element of opinio juris asa means to prove the existence of certain customary norms, insistingon its necessity and relevance in the formation of custom, when, forexample, States disputed the content of customary law 492. Just assignificant was the fact that H. Kelsen and P. Guggenheim them-selves gradually recognized the necessity to abandon their argu-ments, yielding to the recognition of the continued viability, andnecessity, of the opinio juris ; to prescind from this latter would onlybenefit the powerful, besides incurring into the error of equating lawwith mere State conduct 493. Opinio juris came to attract growing


494. Cf. M. Sørensen, op. cit. supra footnote 473, p. 85. On R. Ago’s view ofa “spontaneous” customary international law, cf. comments by J. J. Lador-Lederer, “Some Observations on the ‘Vienna School’ in International Law”, 17Nederlands Tijdschrift voor internationaal Recht (1970), pp. 137-138. This viewwas opposed by J. L. Kunz, “The Nature of Customary International Law”,op. cit. supra footnote 492, pp. 664-665.

495. Cf. remarks in P. Guggenheim, Traité de droit international public,Vol. I, Geneva, Libr. Univ. Georg & Cie., 1953, pp. 46-48 and 506 ; cf. alsoH. W. Briggs, “The Colombian-Peruvian Asylum Case and Proof of CustomaryInternational Law”, 45 AJIL (1951), pp. 728-731, esp. p. 729.

496. Cf. A. A. Cançado Trindade, “The Burden of Proof with Regard toExhaustion of Local Remedies in International Law”, 9 Revue des droits del’homme/Human Rights Journal, Paris (1976), pp. 81-121 ; and cf. the memo-randum of the UN Secretary-General, Ways and Means of Making the Evidenceof Customary International Law More Readily Available, New York, UnitedNations Pub. No. 1949-V-6, 1949, pp. 3-114.

497. M. Virally, “The Sources of International Law”, Manual of PublicInternational Law (ed. Max Sørensen), London, MacMillan, 1968, p. 139.

498. Cf. cit. in C. Parry, The Sources and Evidences of International Law,Manchester, University Press, Oceana, 1965, pp. 58 and 62, and cf. pp. 56-82 ;C. Parry, “The Practice of States”, 44 Transactions of the Grotius Society (1958-1959), pp. 167 and 159, and cf. pp. 145-186.

attention on the part of international legal doctrine 494, and nowadaysits wide scope is duly recognized (infra).

The proof of custom, object of attention on the part of the ICJ inthe Asylum (Colombia v. Peru) case (1950) 495, was to abide by theprinciple of division or distribution of the burden of proof (onusprobandi incumbit actori) between the contending parties in interna-tional litigation 496. A problem emerged at the epoch of decoloniza-tion was that of determining the application or not of customaryInternational Law to the new States, then recently emancipated politi-cally. The question appeared initially surrounded by uncertainties. Ifone was to apply the positivist theory of consent as the ultimatefoundation of International Law, serious difficulties would arise, asonly the norms with which the new States would entirely agreewould be automatically binding upon them ; it is known, however,that, in practice, new States preferred, instead of trying promptly toreject certain norms which could appear adverse to them, to admittheir existence and to endeavour to change them and to ensure effec-tively their evolution by means of their conscious and concertedaction to this effect in international forums like the United NationsGeneral Assembly.

And this, in fact, brought about significant changes in contempo-rary International Law 497. In the past, International Law was charac-terized as “the generalization of the practice of States” 498 ; nowa-


499. A. A. Cançado Trindade, O Direito Internacional em um Mundo emTransformação, Rio de Janeiro, Ed. Renovar, 2002, pp. 1048-1049.

500. Including bilateral and multilateral treaties, resolutions of the UNGeneral Assembly, resolutions of scientific associations such as the Institut deDroit International and the International Law Association ; cf. M. Akehurst,“Custom as a Source of International Law”, 47 BYBIL (1974-1975), pp. 13-14,18-19, 23 and 51.

501. E.g., resolutions 1721 (XIV), 1802 (XVII), 1962 (XVIII) and 1963(XIX), and particularly resolution 1962 (XVIII), of the UN General Assembly.

502. G. Arangio-Ruiz, “The Normative Role of the General Assembly of theUnited Nations and the Declaration of Principles of Friendly Relations”, 137RCADI (1972), p. 525.

503. It is known, today, however, that the “agreement” between the twosuperpowers of the epoch — the United States and the Soviet Union — whichrendered the adoption of such resolutions possible did not pass without contro-versy. As to the form of such “agreement”, while the Soviet Union preferred atreaty, the United States insisted on a resolution of the General Assembly, a for-mula which the Soviet Union was finally persuaded to accept.

days, international practice has a much wider scope, comprising notonly that of States, but also that of international organizations and ofother subjects of International Law 499. In fact, as much of the prac-tice of States remains — with notable exceptions — largely unpub-lished and not examined (sometimes simply unrecorded), for thedetermination of the proof of custom resort has often been made to amass of other available materials 500, at times transcending the prac-tice of States themselves. In any case, no State — however powerfulit might be — can claim that its individual practice is intrinsicallymore important than that of other States (just because of the publi-city and dissemination given to it) ; as members of the internationalcommunity, they all contribute, altogether, to the formation anddevelopment of international practice, jointly with other subjects ofInternational Law.

Another issue relating to international custom is that of the moreor less “immediate” creation of customary norms in new areas ofInternational Law, in which there was no prior regulation. A remark-able example was provided by the United Nations General Assemblyresolutions in the early sixties, on the exploration and use ofspace 501, resulting in great part from a “tacit agreement” between thetwo main space actors of the epoch, and which were to reflect, in theview of some authors, an “inchoate custom” on the matter 502.Resolutions 1721 (XVI), of 20 December 1961, and 1962 (XVIII),of 13 December 1963, were to be acclaimed as the “initial chapter”of the treatment of contemporary space law 503. It was at that timesuggested that this solution represented an “instant customary law”


504. Bin Cheng, “United Nations Resolutions on Outer Space : ‘Instant’International Customary Law ?”, 5 Indian Journal of International Law (1965),pp. 23-48 ; and cf. comments by I. Herczeg, “Space Treaties and Law-MakingProcess in International Law”, in Questions of International Law (ed. HungarianBranch of the International Law Association), Budapest, Progressprint, 1971,pp. 51-63, esp. p. 53.

505. Cf. criticisms by Maarten Bos, op. cit. supra footnote 478, pp. 27 and 68.506. Cf. ICJ Reports 1969, p. 44, para. 77.507. ICJ Reports 1985, pp. 29-30, para. 27.508. ICJ, Advisory Opinion on the Threat or Use of Nuclear Weapons, ICJ

Reports 1996, p. 253, para. 64.509. International case-law points in the sense that constitutional or domestic

law provisions cannot be invoked to evade international obligations and cannotprevail over provisions of treaties in force.

510. Lord McNair, “Treaties and Sovereignty”, in Symbolae Verzijl (présentésau professeur J. H. W. Verzijl à l’occasion de son soixante-dixième anniver-saire), The Hague, M. Nijhoff, 1958, pp. 222-237 ; R. Ago, “Third Report onState Responsibility”, Yearbook of the International Law Commission (YILC)(1971-II), Part I, pp. 226-233.

for the aforementioned activity of regulation 504, an expression whichalso attracted a certain controversy 505 at that time.

The ICJ itself, in its turn, has made it clear, as to the acknow-ledgment of custom, that it would look into both elements — actualpractice and opinio juris. It did so in the North Sea Continental Shelfcases (1969) 506, and, again, in the Continental Shelf (Libya v. Malta)case (1985) 507. Over a decade later, the point was retaken by the ICJ,in an Advisory Opinion delivered on 8 July 1996 508.

2. Treaties

As to treaties, the first point directly related to the study of theformal “sources” of International Law pertains to the proper rela-tionship between treaties and the notion of State sovereignty. In theWimbledon case (Judgment of 17 August 1923), the PCIJ clarifiedthat the conclusion of treaties, and the faithful compliance withthem, constituted precisely attributes of the sovereignty of the State.This latter cannot be invoked so as to conflict with conventionalobligations 509. This amounts to a principle that governs internationalobligations, a principle of international responsibility and even ofcustomary law : a State cannot evade its international obligationsunder the pretext of their alleged incompatibility with its owndomestic legal order (or any acts — legislative, executive or judicial— emanated from the public power) 510.

Sovereignty does not have a bearing on the interpretation of


511. Lord McNair, op. cit. supra footnote 510, pp. 222-237, esp. pp. 236-237.On the rules of treaty interpretation set forth in Articles 31-33 of the 1969Vienna Convention on the Law of Treaties, cf. M. K. Yasseen, “L’interprétationdes traités d’après la Convention de Vienne sur le droit des traités”, 151 RCADI(1976), pp. 9-112.

512. ICJ, Advisory Opinion on the Applicability of the Obligation toArbitrate under Section 21 of the United Nations Headquarters Agreement of1947, ICJ Reports 1988, p. 34, para. 57.

513. Maarten Bos, op. cit. supra footnote 478, pp. 20-24.514. On the generic term “treaty” under the 1969 Vienna Convention, cf.,

e.g., P. M. Eisemann, “Le gentlemen’s agreement comme source du droit inter-national”, 106 Journal du droit international, Clunet (1979), pp. 326-349, andcf. p. 326 on the insufficiencies of the “dogmatism” of Article 38 of the ICJStatute. Moreover, concerned with practical problems, the two aforementionedVienna Conventions discard abstract classifications of treaties, so common inthe past (such as, e.g., the distinction between traité-contrat and traité-loi) ;S. Rosenne, “Bilateralism and Community Interest in the Codified Law ofTreaties”, in Transnational Law in a Changing Society — Essays in Honour ofPh. C. Jessup (ed. W. Friedmann, L. Henkin and O. Lissitzyn), New York,London, Columbia University Press, 1972, pp. 202-227.

treaties 511 ; every conventional obligation limits the sovereignpowers of States parties. In an Advisory Opinion issued on 26 April1988, the ICJ, holding that the United States was bound to respectthe obligation to have recourse to arbitration under Section 21 of the1947 United Nations Headquarters Agreement, saw fit to recall “thefundamental principle of International Law that International Lawprevails over domestic law” 512.

The impressive and ever-continuing growth only of the UnitedNations Treaty Series, for example, would suffice to attest the greatrelevance of the utilization of treaties in international practice and ofthe rules of conduct derived therefrom. Yet, distinct approaches havebeen propounded as to the consideration of treaties as “source” ofInternational Law. There were those who contended that they wererather “sources” of obligations (G. Fitzmaurice, C. Parry), whileothers disagreed with that posture (A. Verdross) ; in an intermediaryposition, Maarten Bos proposed that treaties are “sources” ofInternational Law to the extent that they increase or codify the cor-pus of already existing rules, and are “sources” of obligations when,rather distinctly, they exert the role equivalent to that of a contract inmodern domestic law 513. The 1969 and 1986 Vienna Conventions onthe Law of Treaties do not provide for the law which governs inter-national obligations of States, but rather and more precisely for thelaw on the international instruments enshrining such obligations, i.e.,the treaties 514.

There is no impediment for treaty provisions to enter into the cor-


515. Cf. the North Sea Continental Shelf (Federal Republic of Germany/Denmark ; Federal Republic of Germany/Netherlands) cases (Judgment of 20 Feb-ruary 1969), ICJ Reports 1969, p. 41.

516. Cf. account in I. M. Sinclair, The Vienna Convention on the Law ofTreaties, Manchester, University Press, Oceana, 1973, pp. 9 and 11.

517. C. Th. Eustathiades, Unratified Codification Conventions (GilbertoAmado Memorial Lecture), Geneva, UN Publ., 1973, pp. 2 and 10.

518. Such as, e.g., the 1969 and 1986 Vienna Conventions on the Law ofTreaties, the 1982 UN Convention on the Law of the Sea, the 1961 ViennaConvention on Diplomatic Relations and the 1963 Vienna Convention onConsular Relations.

519. The 1975 Vienna Convention on Representation of States in TheirRelations with International Organizations of Universal Character, e.g., can betaken as declaratory of customary rules on the matter already crystallized evenbefore their adoption.

pus of general International Law, i.e., to generate rules of customaryInternational Law. Such possibility was cautiously admitted by theICJ itself, in the same year of the conclusion of the first ViennaConvention on the Law of Treaties 515. In the account of one partici-pant in the Vienna Conference of 1968-1969, on the occasion therepresentative of Sweden observed that a great part of the contentsof the 1969 Convention expressed simply rules already existing incustomary International Law, while the Swiss representative, in histurn, added that, in order to fill the gaps which persisted, it wasoccasionally “still necessary, in the practice of international rela-tions, to fall back on custom” 516.

Moreover, even certain unratified conventions of general scopemay have a bearing on the formation of international custom.Modern endeavours of codification, which go “much further beyondthe mere expression of customary International Law” than earlierconventions did, have increasingly characterized the “progressivedevelopment” of International Law, in endeavouring to fulfil “exist-ing needs of the international community” 517. It has been concededthat even one or another of the so-called “codification conven-tions” 518 are declaratory of customary law, and, having achieved asignificant number of ratifications, even before entering into forcethey could keep on contributing to the evolving general InternationalLaw itself 519. In this respect, it has been suggested that

“in the case of a codification convention lato sensu, inother words, a convention which codifies and ‘progressivelydevelops’ International Law . . ., the codification process con-sidered independently of ratification may give rise to new cus-


520. C. Th. Eustathiades, op. cit. supra footnote 517, p. 13, and cf. pp. 3-4,7-8 and 12.

521. Cf. Chap. III, supra. 522. P. Guggenheim, “Contribution à l’histoire des sources du droit des

gens”, 94 RCADI (1958), pp. 72-76 and 80-81. 523. Cf., on the point, e.g., M. Virally, op. cit. supra footnote 497, pp. 144-

146. Moreover, while the borderline between treaties and custom appeared clear,not always it appeared easy to distinguish customary rules from general prin-ciples of law. Bin Cheng, General Principles of Law as Applied by InternationalCourts and Tribunals, London, Stevens, 1953, p. 23 ; cf. also the critical remarksby Ch. Chaumont, “Cours général de droit international public”, 129 RCADI(1970), pp. 456-464.

524. Cf. its composition in footnote 476, supra.

tomary rules and thereby alter the rights and obligations ofStates regardless of the consent which the convention requiresfrom them to be valid as such” 520.

3. General principles of law

I have already expressed my view that general principles of lawconform the very foundations of International Law, and indeed ofevery and any legal system 521. At this stage, in approaching the for-mal “sources” of International Law, suffice it here to point out thatthe inclusion of general principles of law among the “sources” setforth in Article 38 of the ICJ Statute can be more clearly explainedas from the outlook of the natural law foundations of InternationalLaw. Such inclusion, moreover, came to endorse the findings ofearlier arbitral practice, which contributed to the configuration ofa third “source” of International Law, historically more recent thancustom and treaties 522. There persisted, however, doubts and uncer-tainties as to the meaning of general principles of law ; for example,for some, the expression pertained to the principles of InternationalLaw properly, while for others it referred to the principles of com-parative domestic law of the various States 523.

The doubts and uncertainties already referred to were madepresent during the drafting itself, by the Advisory Committee ofJurists appointed to that end 524, of Article 38 of the Statute of theHague Court in June-July 1920. Baron Descamps, who believed in“objective justice” (present in theories of natural law), proposedoriginally to the Committee the expression “juridical conscience ofthe civilized nations”, against whose “subjectivism” Mr. E. Rootmanifested himself. Lord Phillimore elaborated, together withE. Root, an amendment to the proposal of Descamps. The solution


525. Bin Cheng, op. cit. supra footnote 523, pp. 6-21 ; Maarten Bos, op. cit.supra footnote 478, pp. 33-39.

526. There have been calls for a thorough survey of comparative law for theidentification of the general principles of law ; cf. M. Akehurst, “Equity andGeneral Principles of Law”, 25 International and Comparative Law Quarterly(1976), pp. 817-819 ; A. A. Cançado Trindade, “La méthode comparative endroit international : une perspective européenne”, 55 Revue de droit interna-tional de sciences diplomatiques et politiques (1977), pp. 273-287 ; L. C. Green,“Comparative Law as a ‘Source’ of International Law”, 42 Tulane Law Review(1967), pp. 52-66.

527. Bin Cheng, op. cit. supra footnote 523, p. 23, and cf. pp. 25-26. On theusefulness to international tribunals to resort to general principles of law, cf. M.O. Hudson, International Tribunals — Past and Future, Washington, CarnegieEndowment for International Peace, Brookings Institution, 1944, p. 108.

528. On judicial precedent as source of International Law, cf. H. Lauterpacht,The Development of International Law by the International Court, London,Stevens, 1958, pp. 20-22 ; J. G. Merrills, The Development of International Lawby the European Court of Human Rights, 2nd ed., Manchester, University Press,1993, pp. 12-16 and 231-233 ; J. R. W. D. Jones, The Practice of theInternational Criminal Tribunals for the Former Yugoslavia and Rwanda, 2nded., Ardsley N.Y., Transnational Publs., 2000, pp. 3-643 ; L. J. van den Herik,

of compromis, between the principles of “objective justice” ofDescamps, and the principles of “common law” (Phillimore) or recog-nized by “civilized nations” in foro domestico (Root), came intooperation with the expression “general principles of law” 525.

The expression incorporated, however, the tension of the polaritybetween jusnaturalism (the universal principles of objective justice)and legal positivism (the search for the principles of law recognizedand crystallized in the domestic legal orders). It is, however, clearthat the expression establishes a clear link between domestic law andInternational Law 526. As from the fifties reiterated references cameto be made to general principles of law such as those of good faith,of res judicata, of the prohibition of the abuse of rights, amongothers. It has been argued that Article 38 of the Statute of theHague Court, as adopted (i.e., containing references inter alia tocustom and general principles of law), came to reject the thesis thatonly the rules created by means of a “formal process” were “valid”,and to sustain that, like in the domestic legal systems, InternationalLaw also embodies certain principles not formally formulated 527.

4. Judicial and arbitral decisions

Another formal “source” of International Law, listed in Article 38of the ICJ Statute, lies in the great mass of judicial and arbitral deci-sions 528, which vary in weight and influence. The tribunals (includ-


The Contribution of the Rwanda Tribunal to the Development of InternationalLaw, Leiden, Nijhoff, 2005, pp. 1-284 ; Bin Cheng, “The Contribution ofInternational Courts and Tribunals to the Protection of Human Rights underInternational Customary Law”, in International Protection of Human Rights —Proceedings of the VIIth Nobel Symposium (eds. A. Eide and A. Schou, Oslo,1967), Stockholm, Almqvist & Wiksell, 1968, pp. 167-175 ; among others.

529. Cf., e.g., R. A. Falk, The Role of Domestic Courts in the InternationalLegal Order, Syracuse University Press, 1964, pp. 21-52 and 170 ; F.Morgenstern, “Judicial Practice and the Supremacy of International Law”, 27BYBIL (1950), p. 90. The practice of domestic tribunals in matters of interna-tional law has in fact been taken into account in the case-law of international tri-bunals themselves. Cf., e.g., J. A. Barberis, “Les arrêts des tribunaux nationauxet la formation du droit international coutumier”, 46 Revue de droit internationalde sciences diplomatiques et politiques (1968), pp. 247-253.

530. C. H. Schreuer, “The Authority of International Judicial Practice inDomestic Courts”, 24 International and Comparative Law Quarterly (1975),pp. 180-183 ; A. A. Cançado Trindade, “Exhaustion of Local Remedies inInternational Law and the Role of National Courts”, 17 Archiv des Völkerrechts(1977-1978), pp. 333-360. The old controversies between monism and dualismyield to a new approach to these aspects of the matter ; cf. A. Drzemczewski,“Les faux débats entre monisme et dualisme — droit international et droitfrançais : l’exemple du contentieux des droits de l’homme”, 51 Boletim daSociedade Brasileira de Direito International (1998), Nos. 113-118, pp. 95-109 ;G. Sperduti, “Dualism and Monism : A Confrontation to Be Overcome”, 3 ItalianYearbook of International Law (1977), p. 31.

531. Cf. Chap. XXV, RCADI, Vol. 317 (2005).

ing the arbitral ones) wherefrom they emanate comprise both theinternational and national ones, these latter when pronouncing onquestions of International Law 529. There is here an area of signi-ficant interaction in the operation of international and nationaltribunals ; just as judicial decisions of international tribunals canclarify certain questions of International Law and also of domesticlaw, judicial decisions of national tribunals can likewise do sowhen dwelling upon questions of International Law 530.

Although Article 38 of the ICJ Statute refers to judicial decisionsas a “subsidiary means” for the determination of rules of law, theinternational judicial function has considerably enlarged since thatprovision was drafted, in 1920. At that time, the PCIJ had just beenestablished. Nowadays, besides its successor, the ICJ, the interna-tional community counts on a multiplicity of international tribunals— a phenomenon which discloses the advances achieved in the lastdecades by the old ideal of the realization of international justice 531.Such tribunals today operate in distinct areas of International Law,such as the international protection of human rights, the internationallaw of the sea, international criminal law, the law of integration atthe regional level. Accordingly, judicial decisions as “source” ofInternational Law are bound to increase in importance.


532. A. A. Cançado Trindade, “La perspective trans-atlantique : La contribu-tion de l’œuvre des cours internationales des droits de l’homme au développe-ment du droit public international”, in La Convention européenne des droits del’homme à 50 ans — Bulletin d’information sur les droits de l’homme, No. 50(special issue), Strasbourg, Council of Europe, 2000, pp. 8-9 (published also inother idioms of the Council of Europe) ; and cf. A. A. Cançado Trindade, “TheCase-Law of the Inter-American Court of Human Rights : An Overview”, inStudi di Diritto Internazionale in Onore di G. Arangio-Ruiz, Vol. III, Naples, Ed.Scientifica, 2004, pp. 1873-1898 ; H. Tigroudja and I. K. Panoussis, La Courinteraméricaine des droits de l’homme — Analyse de la jurisprudence consul-tative et contentieuse, Brussels, Bruylant, Nemesis, 2003, pp. 21-308.

Contemporary international tribunals pronounce, more and moreoften, on questions of interest of, or concern for, the internationalcommunity as a whole. Judicial decisions of the international humanrights tribunals — the European and Inter-American Courts ofHuman Rights —, for example, have indeed contributed to thecreation of an international ordre public based upon the respect forhuman rights in all circumstances. They have both helped to achievethe aptitude of International Law to regulate efficiently relationswhich have a specificity of their own — at intra-State, rather thaninter-State, level, opposing States to individuals under their respec-tive jurisdictions ; they have thus contributed to enrich and humanizecontemporary International Law 532.

Judicial decisions of the ad hoc international criminal tribunals —those for the former Yugoslavia and for Rwanda —, for example,have, in their turn, contributed to combat impunity and to foster therule of law at national and international levels. These reassuringdevelopments are bound to confer a new dimension on internationalcase-law, distinct from that which was envisaged in 1920. This newdimension encompassing contemporary international-law-makingreflects, in turn, the recent advances towards international ordrepublic and rule of law, proper to the newly emerging jus gentium atthis beginning of the twenty-first century.

5. Doctrine

Article 38 (1) (d) of the Statute of the Hague Court indicatesexpressly, moreover, that doctrine also constitutes a “subsidiarymeans”, among the “sources” listed therein. The reference to doc-trine is accompanied by a qualification, namely, “the teachings of themost highly qualified publicists of the various nations”. The influ-ence of some distinguished authors has appeared more remarkable in


533. Cf. Chap. I, supra.534. E. M. Borchard, The Diplomatic Protection of Citizens Abroad, New

York, Banks Law Publ. Co., 1916, pp. 1 ff. ; and cf. C. Parry, The Sources andEvidences of International Law, Manchester, University Press, Oceana, 1965,p. 107.

535. Although States had claimed restricted rights in areas adjacent to theirterritorial sea well before Gilbert Gidel started writing on such claims (cf.G. Gidel, Le droit international public de la mer, 3 vols., Châteauroux,Mellottée, 1932-1934), “it was Gidel who produced the concept of contiguouszone as a basis for the discussion about the validity of such claims”(M. Akehurst, A Modern Introduction to International Law, 2nd ed., London,G. Allen & Unwin, 1971, pp. 55-56).

536. Cf., recently, A. A. Cançado Trindade and A. Martínez Moreno,Doctrina Latinamericana del Derecho Internacional, Vol. I, San José of CostaRica, Inter-American Court of Human Rights, 2003, pp. 5-64.

537. N. Mateesco, Doctrines-écoles et développement du droit des gens,Paris, Pedone, 1951, pp. 25 and 45.

the epoch of formation of International Law than subsequently, asexemplified by the writings of the classics 533. Although there is atendency to attribute to doctrine nowadays a rather modest positionamong the “sources” of International Law, one ought not, however,neglect it. Resort is always made to doctrinal teachings, for example,at least to substantiate claims at the international level.

There have also been instances, however rare, of individualauthors who have succeeded in influencing the evolution itself ofInternational Law in specific domains, such as diplomatic protectionof nationals abroad 534, and the law of the sea 535, among others.Furthermore, the considerable influence may be recalled, forexample, of Latin American doctrine (especially that of a defen-sive character) for the general recognition of certain principles ofInternational Law, such as those of the juridical equality ofStates, of non-use of force and non-intervention in inter-State rela-tions (the Drago and Calvo doctrines), and of peaceful settlementof international disputes 536.

Some have regarded, as a limitative characteristic of doctrine (inthe sense of the teachings of publicists), its alleged tendency toreflect the perceptions of International Law prevailing in a givenlegal system, region or country. Be that as it may, the insertion ofdoctrine among the formal “sources” of International Law set forthin Article 38 of the ICJ Statute is not to be minimized. It should bekept in mind that, in historical perspective, some of the great doc-trines of International Law, crystallized with the passing of time,have contributed to the “development of the juridical conscience”and have fostered the sentiment of international solidarity 537. The


538. M. Lachs, The Teacher in International Law, 2nd rev. ed., Kluwer,Nijhoff, 1987, pp. 159-229.

539. A. de La Pradelle, Maîtres et doctrines du droit des gens, 2nd ed., Paris,Editions internationales, 1950, p. 7.

540. Ibid., pp. 7-8.541. Cf. United Nations, The Work of the International Law Commission, 5th

ed., New York, United Nations, 1996, pp. 1-501.542. Reproduced in its series Recommendations and Reports.543. Cf., e.g., inter alia, AALCC, Asian-African Legal Consultative

Committee — Report and Selected Documents (XXXII Session, 1993), NewDelhi, AALCC Secretariat, 1993, pp. 1-312.

544. Such as, in particular, the Institut de Droit International, and also theInternational Law Association, the Instituto Hispano-Luso-Americano deDerecho Internacional (IHLADI), among others.

545. Cf. Institut de Droit International, Livre du Centenaire 1873-1973 :Evolution et perspectives du droit international, Basle, Karger, 1973, pp. 124-473 ; G. Fitzmaurice, “The Contribution of the Institute of International Law tothe Development of International Law”, 138 RCADI (1973), pp. 211-259 ;

influence of the teachings in the domain of International Law, aswell pointed out by M. Lachs, projects itself well beyond the peda-gogical sphere, reaching the practice itself of International Law 538.

And as well pointed out also by A. de La Pradelle, while interna-tional judges and arbiters have remained aware of the self-limita-tions inherent in their functions, and representatives of States haveonly and invariably beheld their own interests, not seldom in a ratheruncompromising way — doctrine, in its turn, has retained its cre-ative function 539. It is important — he added — that the inspirationof the human spirit devotes itself freely to the search for “juridicaltruth”, keeping forcefully in mind that the establishment of rules,regarded as obligatory for States “independently of their formal con-sent”, could not be undertaken by the States themselves 540.

It is, moreover, to be borne in mind that doctrine is not limited tothe teachings of individual authors, but comprises, likewise relatedto the “sources” of International Law, the relevant doctrinal workemanated from collegiate organs within international organizations(for example, the work of the United Nations International LawCommission 541, of the OAS Inter-American Juridical Committee 542,and the Asian-African Legal Consultative Committee 543, devoted tothe realization of the aims of codification and progressive develop-ment of International Law), or else from international scientific-academic institutes or associations 544, whose Yearbooks and Reportscontain a wealth of materials reflecting the evolving doctrine ofInternational Law 545 and dealing with themes of concern to the inter-national community as a whole.


International Law Association, The Present State of International Law — 1873-1973, Kluwer, Deventer, 1973, pp. 3-392 ; P. De Visscher, “La contribution del’Institut de droit international à la protection des droits de l’homme”, in Ledroit international au service de la paix, de la justice et du développement —Mélanges M. Virally, Paris, Pedone, 1991, pp. 215-224 ; Ch. Dominicé, “La con-tribution de l’Institut de droit international au développement du droit de l’or-ganisation internationale”, in Mélanges en l’honneur de N. Valticos — Droit etjustice (ed. R.-J. Dupuy), Paris, Pedone, 1999, pp. 101-115.

546. Cf. M. Sørensen, op. cit. supra footnote 473, pp. 28-33.547. On these latter, cf., e.g., Ch. Rousseau, Droit international public, Vol. I,

Paris, Sirey, 1970, pp. 400-405.548. As set forth in Article 38 (2) of the Statute of the Hague Court.549. M. Akehurst, “Equity and General Principles of Law”, 25 International

and Comparative Law Quarterly (1976), pp. 801-813. 550. Ch. De Visscher, De l’équité dans le règlement arbitral ou judiciaire des

litiges de droit international public, Paris, Pedone, 1972, pp. 6-7, and cf. pp. 12-13.551. M. Akehurst, op. cit. supra footnote 549, pp. 811-812 ; Ch. De Visscher,

op. cit. supra footnote 550, p. 4.

6. Equity

In the course of the drafting, in 1920, of Article 38 of the PCIJStatute, the Advisory Committee of Jurists (appointed to that end)conceived the function of equity as being very restricted, to beapplied only if agreed upon by the parties 546. In fact, the notion ofequity, which by Article 38 (2) of the Statute (of the PCIJ and theICJ) occupies only a secondary position among the “sources” ofInternational Law, was surrounded by uncertainties 547 ; Article 38 (2)limits itself to preserve “the power of the Court to decide a case exaequo et bono, if the parties agree thereto”. According to the well-known classification of the functions of equity, this latter may beapplied infra legem (adapting the law to the facts of concrete cases),praeter legem (filling gaps in law), or contra legem (as a means torefuse to apply unjust laws). It is generally reckoned that equity con-tra legem could not be applied in the absence of an express autho-rization in this sense 548 ; equity praeter legem is currently of reducedapplication, given the unlikelihood of gaps in International Lawnowadays. There thus remains equity infra legem, the most usualform of its application, as, for example, in frontier disputes 549.

Charles De Visscher once remarked that equity is “characterizedessentially as an individualized expression of justice” 550. Because ithas tended to be identified with a certain subjectivism, internationaltribunals have often joined references to equity to a simultaneousinvocation of custom, or of treaties, or of general principles of law,or of earlier judicial or arbitral decisions 551. It has been argued that


552. Ch. De Visscher, op. cit. supra footnote 550, p. 9.553. There are those who detected, in the Judgment of 1969 of the ICJ on the

North Sea Continental Shelf (Federal Republic of Germany/Denmark ; FederalRepublic of Germany/Netherlands) case, ICJ Reports 1969, pp. 32-33, 49-50and 53-54, paras. 47, 91-92 and 100), an example of a decision based on “con-siderations of equity” ; K. Hjertonsson, The New Law of the Sea — Influence ofthe Latin American States on Recent Developments of the Law of the Sea,Leiden, Stockholm, Sijthoff, Norstedts, 1973, p. 166, and cf. pp. 163-168.

554. B. G. Ramcharan, “Equity in the International Law of Human Rights”, 5Dalhousie Law Journal (1979) pp. 52, 59 and 65-66.

555. N. K. Hevener and S. A. Mosher, “General Principles of Law and theU.N. Covenant on Civil and Political Rights”, 27 International and ComparativeLaw Quarterly (1978), pp. 596-597, 601, 603-604 and 612-613.

556. Cf., e.g., G. Venturini, “La portée et les effets juridiques des attitudes etdes actes unilatéraux des Etats”, 112 RCADI (1964), pp. 387-388, 391 and 400-401 ; and cf. A. Miaja de la Muela, “Los Actos Unilaterales en las RelacionesInternacionales”, 20 Revista Española de Derecho Internacional (1967),pp. 456-459.

557. E. Suy, Les actes juridiques unilatéraux en droit international public,Paris, LGDJ, 1962, p. 44.

it remains incumbent upon equity to keep on proceeding to the“judicial adaptation of the rules to the circumstances of the concretecases” 552.

Considerations of equity have been invoked in internationaljudicial practice, for example in the domains of the law of the sea 553,and of the international protection of human rights (in this latter, forexample, in the acknowledgment of powers “inherent” in interna-tional supervisory organs 554 and in the determination of reparationsto victims), thus discarding State voluntarism 555.

IV. The Formal “Sources” Not Enumerated in Article 38of the ICJ Statute

1. Unilateral juridical acts of States

Given the decentralization of the international legal order, inwhich co-exist, in a regime of co-ordination, politically organizedentities such as the States (besides international organizations,peoples and individuals), it is not surprising that unilateral actsemanating from them have had legal effects attached thereto. Inter-national practice has admitted, in fact, that international obligationsmay be assumed under certain circumstances as a result of someunilateral acts 556. Unilateral acts have, as a matter of fact, been con-ceived as manifestations of a subject of International Law to whichthis latter attaches certain consequences 557. There are unilateral acts


558. P. Reuter, Institutions internationales, 6th ed., Paris, PUF, 1969,pp. 120-128 ; and cf. Chap. VII, infra.

559. Cf. examples in, e.g., Alf Ross, A Textbook of International Law —General Part, London, Longmans, 1947, pp. 118-122 ; and cf. E. Suy, op. cit.supra footnote 557, pp. 189-214.

560. J. Dehaussy, “Les actes juridiques unilatéraux en droit internationalpublic : à propos d’une théorie restrictive”, 92 Journal du droit international,Clunet (1965), pp. 55-56, and cf. p. 63.

561. This was what also happened, at a given time, with the extension of theterritorial sea to a limit of 200 miles on the part of some Latin American States,by means of “internal” unilateral acts (proclamations, laws, decrees, etc.). Thiswas, furthermore, what happened with the continental shelf as from the well-known proclamation by Truman of 1945.

562. A. A. Aramburu Menchaca, “La Costumbre y la Delimitación de losEspacios Marítimos en el Continente Americano”, 38 Revista de Derecho yCiencias Políticas, Lima, Peru (1974), pp. 5-39 ; cf. also K. Hjertonsson, op. cit.supra footnote 553, pp. 7-179.

563. Such as that of the exclusive economic zone, as from the territorial seaof 12 miles.

foreseen by customary law, for example protest, notification, promise,renunciation, recognition, among others.

Even such acts do not pass without qualifications. Recognition,for example, is often a unilateral act, based largely on the prin-ciple of effectiveness in a given situation, with the consequencesensuing therefrom 558. On the other hand, non-recognition is alsoutilized in practice to try to impede that a situation de facto (forexample, one generated by force) comes to produce legal effects 559.Proposed enumerations of unilateral acts in International Law havenot purported to be exhaustive 560, or conclusive as to their legaleffects.

Yet, it is to be recalled that, in the domain of the law of the sea,for example, the notions of contiguous zone, territorial sea (followedby patrimonial sea and subsequently exclusive economic zone) wereinitially formed (before the 1982 UN Convention on the Law of theSea) by means of unilateral acts of regulation on the part of eachState individually rather than by means of multilateral treaties 561. Itwas suggested that the constant repetition of these multiple unilateralacts, for more than three decades before the adoption of the 1982Montego Bay Convention, contributed decisively to the formation ofsome customary norms in this domain 562. With the adoption, how-ever, of the 1982 UN Convention on the Law of the Sea, some ofthem were consolidated therein, while other emerging conceptswhich appeared to reflect a more generalized consensus wereadopted therein 563.


564. Cf. J. Dehaussy, op. cit. supra footnote 560, pp. 45, 53-54 and 59-61 ;A. Miaja de la Muela, op. cit. supra footnote 556, pp. 431-434.

565. According to a definition proposed in 1956 to the UN International LawCommission, by international organization it was understood an entity estab-lished by a treaty, with a constitution and common organs, and a personality dis-tinct from that of its member States, being a subject of International Law withcapacity to conclude treaties ; cit. in Yearbook of the International Law Com-mission (1956-II), p. 108 ; the definition was proposed by G. G. Fitzmaurice,rapporteur on the law of treaties.

566. On their contribution to the formation of international custom, cf. L.Kopelmanas, “Custom as a Means of the Creation of International Law”, 18BYBIL (1937), p. 151. In recent decades there remained no doubt that the prac-tice of International Law was no longer restricted to the practice of States, andcomprised also that of international organizations, in need of systematization ;cf., e.g., S. Rosenne, Practice and Methods of International Law, London, NewYork, Oceana Publs., 1984, pp. 1-117.

567. Cf. Chap. VIII, infra. 568. K. Skubiszewski, “A New Source of the Law of Nations : Resolutions of

International Organisations”, in Recueil d’études de droit international en hom-mage à P. Guggenheim, Geneva, IUHEI, 1968, pp. 508 and 510-511, and cf.pp. 518-520. On the juridically relevant activity of the UN Secretariat, cf., e.g.,O. Schachter, “The Development of International Law through the LegalOpinions of the United Nations Secretariat”, 25 BYBIL (1948), pp. 91-132.

569. Cf., e.g., ICJ, Advisory Opinions on Judgments of the AdministrativeTribunal of the ILO upon Complaints Made against Unesco (1956), and onCertain Expenses of the United Nations (1962).

2. Resolutions of international organizations

Some attempts were made in the past to approach unilateral actsof States and acts of international organizations jointly 564. Thisapproach, however, gave margin to some uncertainties, and it soonappeared more appropriate to consider the acts of international orga-nizations separately from the unilateral acts of States. In fact, withthe advent and growth of international organizations 565, as from themid-twentieth century, the gradual expansion of their regulatorypowers, varying from case to case, took place 566. The activities anddecisions of international organizations, in the most diverse sectors,are usually externalized by means of resolutions, of varying rele-vance and scope : some serve as instrument of exhortation, othersenunciate general principles, and others require a given type ofaction aiming at specific results 567.

Resolutions of international organizations have a specificity oftheir own, being distinct from other categories of “sources” enumer-ated in Article 38 of the ICJ Statute 568. Significantly, the silence,about them, of that provision, has not impeded the ICJ to take thempromptly and properly into account 569. In various passages of itsAdvisory Opinion of 16 October 1975 on the Western Sahara, for


570. In the context of decolonization and self-determination ; cf. ICJ Reports1975, pp. 20, 23, 26-37, 40, 57 and 67-68.

571. Cit. in Ch. Schreuer, “Recommendations . . .”, op. cit. supra foot-note 488, p. 112 and n. 42.

572. ICJ, Advisory Opinion on the Threat or Use of Nuclear Weapons, ICJReports 1996, pp. 254-255, para. 70.

573. Cf. ICJ Reports 2004, pp. 171-172, paras. 86-88.

example, the ICJ considered and discussed in detail some resolutionsof the UN General Assembly 570. Earlier on, the UN GeneralAssembly itself, in its resolution 3232 (XXIX) of 22 November1970, about the revision of the function of the ICJ, also espoused thethesis that the development of International Law can be reflected,inter alia, in declarations and resolutions of the UN GeneralAssembly, which can to this effect be thus taken into account by theICJ 571.

This is in fact what has happened in practice. In a subsequentAdvisory Opinion, of 8 July 1996, the ICJ has asserted that

“General Assembly resolutions, even if they are not binding,may sometimes have normative value. They can, in certain cir-cumstances, provide evidence important for establishing theexistence of a rule or the emergence of an opinio juris. Toestablish whether this is true of a given General Assembly reso-lution, it is necessary to look at its content and the conditionsof its adoption ; it is also necessary to see whether an opiniojuris exists as to its normative character. Or a series of resolu-tions may show the gradual evolution of the opinio jurisrequired for the establishment of a new rule.” 572

And, more recently, in its Advisory Opinion of 9 July 2004 onthe Legal Consequences of the Construction of a Wall in theOccupied Palestinian Territory, the ICJ observed that principles andrules of International Law (for example, pertaining to the prohibitionof threat or use of force, and to the self-determination of peoples)can be found in the UN Charter and certain other treaties, in cus-tomary International Law and in the relevant resolutions adopted bythe UN General Assembly and the Security Council 573. In fact, justas unilateral juridical acts of States (as subjects of InternationalLaw) rank among the formal “sources” of the contemporary law ofnations, so do the juridical acts (resolutions) of international organi-zations (likewise subjects of International Law).


574. B. Sloan, op. cit. infra footnote 575, p. 116, and cf. pp. 74-75.575. B. Sloan, “General Assembly Resolutions Revisited (Forty Years

Later)”, 58 BYBIL (1987), p. 80, and cf. pp. 137 and 141.576. Cf. Ch. Schreuer, op. cit. supra footnote 488, pp. 103-118 ; and cf.

K. Skubiszewski, “Recommendations of the United Nations and MunicipalCourts”, 46 BYBIL (1972-1973), pp. 353-364.

577. Cf. H. G. Schermers and N. M. Blokker, International Institutional Law,3rd rev. ed., The Hague, Nijhoff, 2001, pp. 1-1198 ; C. W. Jenks, The ProperLaw of International Organisations, London, Stevens, Oceana, 1962, pp. 1-267 ;A. A. Cançado Trindade, Direito das Organizações Internacionais, 3rd ed.,op. cit. infra footnote 589, pp. 75-76, and cf. pp. 9-853.

The element of opinio juris may be more predominant in resolu-tions of the declaratory kind ; in any case, resolutions of internationalorganizations, and in particular those of the UN General Assembly,have been accepted as “sources” of International Law not only bythe ICJ by also by other international (arbitral) tribunals 574. Theyoften give expression to values and aspirations of the internationalcommunity as a whole. As pointed out by B. Sloan in his review of40 years of UN General Assembly resolutions,

“principles in Assembly resolutions may be expressions of theethical or moral conscience of mankind, of a general worldconscience, of basic concepts of equity and justice, or of theunderlying spirit and aims of the UN” 575.

Thus, summing up, the category of resolutions of internationalorganizations does rank among the formal “sources” of contempo-rary International Law. Under certain circumstances, some resolu-tions do meet this test of being a means whereby International Lawmanifests itself. And even if certain resolutions are purely recom-mendatory — and, thus, not binding —, they are, nevertheless, juridi-cally relevant, have much influenced international practice, andStates themselves, naturally reluctant to infringe them, considerthemselves at least in the duty to consider them in good faith 576.Those resolutions form today a vast corpus juris 577, turned to regu-lation of matters of concern of the international community as awhole.

V. The Process of Formation of Contemporary International Law :From Consent to Consensus

In the last decades, a great part of legal doctrine has accommo-dated itself to reviewing the list of the formal “sources” of


578. Cf. E. Suy, “The Meaning of Consensus in Multilateral Diplomacy”, inDeclarations of Principles, A Quest for Universal Peace — Liber AmicorumDiscipulorumque B.V.A. Röling, Leyden, Sijthoff, 1977, p. 272.

579. E. Jiménez de Aréchaga, El Derecho Internacional Contemporáneo,Madrid, Tecnos, 1980, pp. 16, 33, 37 and 39.

580. T. O. Elias, “Modern Sources of International Law”, in TransnationalLaw in a Changing Society : Essays in Honour of Ph. C. Jessup (eds.W. Friedmann, L. Henkin and O. Lissitzyn), New York, London, ColumbiaUniversity Press, 1972, pp. 49 and 51, and cf. p. 67.

581. C. Lang, L’affaire Nicaragua/Etats-Unis devant la Cour internationalede Justice, Paris, LGDJ, 1990, pp. 138, 140 and 149.

International Law” ; yet, as already pointed out, the study of the for-mation of International Law is far from exhausting itself in thoseformal “sources”. For roughly half a century (from the early twentiesto the early seventies), the matter at issue was largely considered inthe light of the question of consent in International Law, which wassoon to become surrounded by controversies, not amenable to simpleanswers. By and large, the debates began to oscillate between the oldthesis (upheld by the PCIJ in its Advisory Opinion of 1923 on theStatus of Eastern Carelia) whereby the consent of States was thebasis of international legal obligations (including in peaceful settle-ment of international disputes) — a view which was later on dis-missed by the ICJ in its Advisory Opinions of 1950 on theInterpretation of Peace Treaties, and of 1971 on Namibia — and thenew approach shifting the focus, on the process of formation ofInternational Law, from individual consent to consensus 578.

According to this new outlook (propounded at the beginning ofthe seventies), in the evolution of International Law individual con-sent could never constitute the ultimate “source” of a legal obliga-tion, and the new and clear tendency in favour of consensus in theformation of norms of International Law 579 was “an expression ofthe juridical conscience of the international community” 580. Thistendency was fostered by the formation of consensus in theConferences of codification and progressive development ofInternational Law. In this way, the old positivist posture of search forthe consent of each State individually was challenged and overcome.Subsequently, in the case of Nicaragua v. United States (Merits,1986), the ICJ took another step, and a significant one, in this direc-tion, discarding the thesis of the individual consent and attributingconsiderable importance to opinio juris 581, to the formation of whichnot only States but also international organizations contribute. Thesame emphasis on opinio juris was laid by the ICJ in the case of the


582. Cf. ICJ Reports 1984, p. 299.583. The insertion of custom into Article 38 (1) (b) of the Statute of the

Hague Court, it may be recalled, had been much influenced, when the provisionwas drafted, by the so-called “historical school” of law, which held that its sub-jective element, opinio juris, was seen as reflecting “juridical conscience”.

584. International Law Association/Committee on Formation of Customary(General) International Law, “Final Report of the Committee — Statement ofPrinciples Applicable to the Formation of General Customary InternationalLaw”, in ILA, Report of the LXIX Conference (London, 2000), London, ILA,2000, pp. 32, 41, 60 and 62. And cf. Chap. III, supra.

585. Hence the approach to the “sources” of International Law as from astrictly inter-State outlook, with a reductionist view focusing largely on the con-ventional and customary means, and minimizing the role of general principles oflaw and of doctrine. Underlying this conception, the element of State consentmarks constant presence, culminating in an apology of the so-called “doctrine ofthe persistent objector”, a last refuge of State voluntarism. Cf. P. Weil, “Le droitinternational en quête de son identité. Cours général de droit international pub-lic”, 237 RCADI (1992), pp. 131-201.

586. G. J. H. van Hoof, Rethinking the Sources of International Law,Deventer, Kluwer, 1983, pp. 35, 101, 153 and 162, and cf. pp. 157, 167 and 175.

587. Ibid., pp. 190, 195, 211, 241, 281, 283-284 and 287, and cf. p. 290 ;R. Monaco, “Réflexions sur la théorie des sources du droit international”, inTheory of International Law at the Threshold of the 21st Century — Essays inHonour of K. Skubiszewski (ed. J. Makarczyk), The Hague, Kluwer, 1996,pp. 517-518.

Delimitation of the Maritime Boundary in the Gulf of Maine Area(1984) 582.

In the Nicaragua v. United States case (1986), the ICJ, while re-emphasizing the need for both the objective and subjective elements(State practice and opinio juris 583, respectively), in fact demandedvery little evidence of State practice, and took as clear-cut proof ofopinio juris the 1970 UN Declaration on Principles of InternationalLaw concerning Friendly Relations among States, the contents ofwhich it regarded as indeed reflecting rules of customary law 584. Ontheir part, positivist doctrines, apparently obsessed only with juridi-cal stability and certainty 585, seemed, on the other hand, to have kepton overlooking values and ideas, and opinio juris itself, and mini-mizing principles which emanate from the “juridical conscience ofmankind”, often expressly invoked in international practice 586. Theconsiderable expansion of International Law came to require a newoutlook of its “sources”, which are ineluctably linked to the funda-mental questions that it deals with ; as pertinently remarked byG. F. H. van Hoof and R. Monaco, traditional “sources” of Inter-national Law no longer succeeded to comprise the whole andincreasingly complex process of its own formation 587.

Thus, the classic theory of the formal “sources”, for example, did


588. R. Monaco, “Réflexions sur la théorie des sources . . .”, op. cit. suprafootnote 587, pp. 519-520 and 529 ; and cf. R. Monaco, “Fonti e Pseudo Fontidel Diritto Internazionale”, 61 Rivista di Diritto Internazionale (1978), p. 740.

589. A. A. Cançado Trindade, Direito das Organizações Internacionais, 3rded., Belo Horizonte, Brazil, Edit. Del Rey, 2003, pp. 721-747.

590. C.-A. Fleischhauer, “The United Nations at Fifty”, 38 German Yearbookof International Law (1995), p. 23.

591. A. G. López Martin, “La Codificación del Derecho Internacional en elUmbral del Siglo XXI : Luces y Sombras en la Labor de la CDI”, 15 Anuario delInstituto Hispano-Luso-Americano de Derecho Internacional (2001), pp. 388-390.

592. Cf. Chap. IV, supra.593. G. G. Fitzmaurice, “Some Problems Regarding the Formal Sources of

International Law”, in Symbolae Verzijl présentées au Professeur J. H. W. Verzijlà l’occasion de son LXXe anniversaire, The Hague, M. Nijhoff, 1958, pp. 166-167and 173-176.

not take fully into due account the considerable normative produc-tion emanated from international organizations 588 — which deci-sively contributed to the overcoming of the inter-State paradigm ofthe international legal order 589. This contribution of internationalorganizations is reflected in their work of codification and progres-sive development of International Law, which, in its turn, hasfostered the rule of law in international relations 590. Such contribu-tion, in having a direct incidence in the process of formation ofInternational Law, represents, moreover, an important stage in theprocess of gradual institutionalization of the international commu-nity, bearing in mind the basic principles of International Law 591.

These principles 592 have an inherent validity and necessity,emanate from natural law, and demonstrate — as categoricallypointed out by G. G. Fitzmaurice — that consent can never consti-tute the ultimate source of International Law, and respond for itsown validity : such voluntarist-positivist position was inconsistent,since consent, externalized by treaties or by State practice, was exhypothesi incapable of explaining or justifying its own validity or itslegal effects, nor the existence and validity of the principles of lawessential to every and any legal system. Thus, the classic theory offormal “sources”, reflected in Article 38 of the ICJ Statute, firstly,could not have the pretension of being “exhaustive” and definitive asto those “sources”, and, furthermore, failed to distinguish betweenformal “sources” and the material “source” of International Law ; itlimited itself to enunciate — in a not exhaustive way — elements tobe taken into account in the application of International Law, and itdid so in a rather limited way 593.


594. Cf. R. Pinto, “Tendances de l’élaboration des formes écrites du droitinternational”, in L’élaboration du droit international public (Colloque deToulouse, Société française pour le droit international), Paris, Pedone, 1975,pp. 13-30.

595. Cf., generally, e.g., F. Hondius, “La reconnaissance et la protection desONG en droit international”, 1 Associations transnationales (2000), pp. 2-4 ;J. Ebbesson, “The Notion of Public Participation in International EnvironmentalLaw”, 8 Yearbook of International Environmental Law (1997), pp. 51-97.

596. Cf. Chap. IX, infra.597. Max Sørensen, Les sources . . ., op. cit. supra footnote 473, pp. 20-21. 598. Ibid., p. 254.

VI. Opinio Juris beyond Custom : Its Wide Scope and Rolein the Formation of Contemporary International Law

In recent years increasing attention has been turned to the ele-ment of opinio juris in the very formation of contemporary Interna-tional Law. To the formation of an “idea of Law” contribute, in ourdays, not only States, but also international organizations and othersubjects of International Law (peoples, individuals and groups ofindividuals). If, some decades ago, it was frequent to approach theprocess of formation of the norms of general International Law withattention turned only to the “sources” manifested in inter-State rela-tions 594, in our days it is no longer possible not to recognize likewisethose ensuing from the practice of entities of the organized civilsociety and of groups of individuals at international level 595. It isnowadays acknowledged that these latter have come to participatein the process both of formation and of application of internationalnorms 596.

The so-called “normativists”, as already pointed out, never man-aged to provide a convincing explanation of the validity of interna-tional legal norms 597, which is a metajuridical question, belonging tothe psychological ambit in which values manifest themselves. Yet, asMax Sørensen lucidly pointed out in the mid-forties, although valuesappear prima facie to transcend the domain of legal science, they areapprehended by acts performed at international level, out of the“intrinsic necessity” to recognize social ends and identify the meansto accomplish them. Thus — he added — International Law cannotbe indifferent to values and moral questions, which always marktheir presence, and International Law ought to attribute “consider-able importance” to general principles of law 598. In this line ofthinking, A. Verdross, in his turn, assumed as foundation of thewhole legal system an “idée du droit”, which has expression pre-


599. I.e., treaties and custom ; ibid., p. 244 ; and cf. A. Verdross, DerechoInternacional Público, 5th ed. (reimprint), Madrid, Aguilar, 1969, pp. 15-19.International Law effectively transcends mere juridical formalism, incapable ofexplaining the origin of its norms ; and it does so precisely in order to fulfil thenew needs of the international community, and without that it would lose itsown raison d’être. N. E. Ghozali, “Les fondements du droit international public— approche critique du formalisme classique”, in Les droits des peuples à dis-poser d’eux-mêmes — Méthodes d’analyse du droit international — Mélangesofferts à Ch. Chaumont, Paris, Pedone, 1984, pp. 305 and 314.

600. A. Truyol y Serra, “Théorie du droit international public. Cours général”,183 RCADI (1981), pp. 142-143.

601. J. A. Carrillo Salcedo, “Derechos Humanos y Derecho Internacional”, 22Isegoría — Revista de Filosofía Moral y Política, Madrid (2000), p. 75.

602. F. Münch, “A propos du droit spontané”, in Studi in onore di GiuseppeSperduti, Milan, Giuffrè, 1984, pp. 149-162 ; F. Münch, “Le rôle du droit spon-tané”, in Pensamiento Jurídico y Sociedad Internacional — Libro-Homenaje al

cisely in the general principles of law, which precede positiveInternational Law 599.

A continuous “rebirth” of natural law has been constantly identi-fied 600, though this latter has never disappeared. This has taken placein face of the hermetic posture of legal positivism, upholding thestatus quo, with its typical subservience to power. It is no longera return to classic natural law, but rather the affirmation or restorationof a higher standard of justice, whereby positive law is assessed.That “rebirth” has much contributed to the assertion and the consoli-dation of the primacy, in the order of values, of the obligations per-taining to the rights of the human person, owed to the internationalcommunity as a whole 601.

Irrespective of the profession or otherwise of a renewed jus-naturalism, it is clear that the enumeration of the “sources”of International Law undertaken by Article 38 of the ICJ Statutehas shown itself — as already pointed out — inadequate and uncon-vincing. Several jusinternationalists have in fact taken a stand mani-festly against the voluntarist-positivist conception which theyregard as underlying the exercise of such enumeration. A notoriousexample was provided by the school of “spontaneous law” (R. Ago,G. Sperduti, R. Quadri, among others), which, in rejecting the enum-eration of the formal “sources”, insisted on the “spontaneous”formation at least of customary international norms, regarded asessentially oriented to the common good.

Underlying this outlook is the moral force of human conscience— the universal juridical conscience — of which, for example, theMartens clause is a manifestation, even as a “general source ofInternational Law” 602.


Prof. D. Antonio Truyol y Serra, Vol. II, Madrid, Universidad Complutense,1986, pp. 831-836.

603. R. Ago, “Nouvelles réflexions sur la codification du droit international”,92 Revue générale de droit international public (1988), p. 540, and cf. p. 541 on“la nature non volontaire de l’origine du droit coutumier”.

604. Ibid., pp. 573-574, and cf. 564-565.605. Cf. A. A. Cançado Trindade, “The Voluntarist Conception of Interna-

tional Law : A Re-Assessment”, 59 Revue de droit international de sciencesdiplomatiques et politiques, Geneva (1981), pp. 201-240.

606. K. Wolfke, “Some Persistent Controversies Regarding Customary Inter-national Law”, 24 Netherlands Yearbook of International Law (1993), pp. 5-6.

607. Ibid., pp. 13-14 and 16.608. R. Huesa Vinaixa, El Nuevo Alcance de la ‘Opinio Juris’ en el Derecho

Internacional Contemporáneo, Valencia, Tirant lo Blanch, 1991, pp. 30-31 and76-77 ; L. Millán Moro, La ‘Opinio Juris’ en el Derecho InternacionalContemporáneo, Madrid, Ed. Centro Est. R. Areces, 1990, pp. 33-34 and 138.

Roberto Ago clearly summarized the outlook of the school of“spontaneous law” :

“une partie essentielle et finalement irremplaçable du droit estcelle qui n’a pas son origine dans des actes volontaires de créa-tion et souvent d’imposition, mais qui s’inscrit spontanément etidéalement dans la conscience des membres d’une sociétéhumaine déterminée, sous l’impulsion d’exigences concrètes etréelles” 603.

He insisted on “the ‘spontaneous’ and hence not voluntary characterof customary International Law”, which moreover presented advan-tages to the complex and evolutive international community 604.

In another line of thinking, but also in reaction against the volun-tarist conception of International Law 605 (reflected, for example, inthe PCIJ decision in the Lotus case, supra), the so-called “historicalschool” of legal thinking emphasized the opinio juris, requiringpractice to be an authentic expression of the “juridical conscience”of nations 606. This conception — though originally circumscribed tothe “juridical conscience” — came subsequently to be developed inthe modern theory of International Law, concerned above all withthe reluctance of certain States to accept and apply norms addressedto a general interest 607.

In fact, the conception of the opinio juris emerged, in the nine-teenth century, as a construction above all of the German historicalschool (Puchta, Savigny), in reaction precisely to the voluntaristconception ; in this way, it succeeded in gradually discarding the“will” of the States, and in moving towards the “common juridicalconscience”, of which the customary norms were an expression 608.


609. At the time of the elaboration of the Statute of the old PCIJ (Article 38,cf. supra), Baron Descamps referred precisely to this common juridical con-science, but, at the end of the debates, there prevailed the reductionist outlook ofcharacterizing opinio juris only as one of the elements (the subjective one) ofcustom ; R. Huesa Vinaixa, El Nuevo Alcance de la “Opinio Juris” . . ., op. cit.supra footnote 608, pp. 36-38.

610. Ibid., pp. 173, 192, 194, 199 and 204-205 ; and cf. R. E. Piza Escalante,“La “Opinio Juris” como Fuente Autónoma del Derecho Internacional (“OpinioJuris” y “Jus Cogens”)”, 39 Relaciones Internacionales, Heredia, Costa Rica(1992), pp. 61-74.

611. Cf. J. I. Charney, “Universal International Law”, 87 American Journal ofInternational Law (1993), pp. 548 and 551, and cf. p. 543 ; J. I. Charney,“International Lawmaking — Article 38 of the ICJ Statute Reconsidered”, inNew Trends in International Lawmaking — International “Legislation” in thePublic Interest (Proceedings of the Kiel Symposium, March 1996), Berlin,Duncker & Humblot, 1997, pp. 180-183 and 189-190.

612. P. Haggenmacher, “La doctrine des deux éléments du droit coutumierdans la pratique de la Cour internationale”, 90 Revue générale de droit interna-tional public (1986), pp. 101, 109 and 124.

This came to foster the formation of these latter in a universalizedinternational community 609. With the passing of time, it became evi-dent that the formation of International Law constituted a muchwider process than the formulation of its formal “sources”, above allin seeking the legitimacy of norms to rule international life. Thismeant a clear distancing from, and abandonment of, classic volun-tarism, and a moving towards the formation of a true “law of con-science” ; in this way, opinio juris came to assume a considerablybroader dimension than that of the subjective element constitutive ofcustom, and to play a key role in the emergence and identification ofthe norms of general International Law 610.

There is a general awareness nowadays of the importance of thework of multiple multilateral forums for the expression of opiniojuris communis and the development of general International Law,diminishing the unilateral influence of the most powerful States, pro-moting international law-making in fulfilment of the public interestand the realization of the common good of the entire international com-munity, and heading towards the universalization of InternationalLaw 611. Opinio juris is affirmed as a key factor in the formation itselfof International Law (and no longer as only one of the constitutiveelements of one of its formal “sources”). The fundamental elementsof the international legal order are independent from the “will” of theStates, and opinio juris gives expression to the “juridical conscience”,not only of nations and peoples (as sustained in the past by the histor-ical school), but of the international community as a whole 612. In


613. And of any community in any epoch ; F. Castberg, “Natural Law andHuman Rights”, 1 Revue des droits de l’homme/Human Rights Law Journal(1968), pp. 34-35 and 37.

614. Cf. Chap. XII, infra.

this way, it fulfils the necessity of an objective validity of the funda-mental principles and norms of the international community 613.

With the abandonment of voluntarist positivism, the primacy ofconscience over “will” seems to have been duly re-established. Ithas, at last, been recognized that conscience refers to superior valueswhich stand above the “will”, and that Law emanates from thecommon conscience of what is juridically necessary (opinio juriscommunis necessitatis). Distinctly from the formal “sources” ofInternational Law, which are nothing more than the means orvehicles of formation of its norms, conscience (expressed in theopinio juris communis) appears distinctly, in my understanding, as itsmaterial “source” par excellence, affirming the binding characterof such norms. It is therefrom, i.e., from the universal juridicalconscience, that the peremptory norms of International Law (juscogens) 614 ultimately emanate.


615. For example, Michel Virally openly stated that what was designated asmaterial “source” would not be of “interest” to the study of International Law ;M. Virally, “Panorama du droit international contemporain. Cours général dedroit international public”, 183 RCADI (1983), p. 167.

CHAPTER VI

THE MATERIAL SOURCE OF INTERNATIONAL LAW :MANIFESTATIONS OF THE UNIVERSAL

JURIDICAL CONSCIENCE

I. Introduction :Insufficiencies of the Formal “Sources” and the Relevance

of the Material “Source” of International Law

The attitude, adopted in the last decades, by part of the interna-tional legal doctrine, of limiting itself, as from an essentially posi-tivist outlook, to consider only the formal “sources” of InternationalLaw, has deprived the consideration of the matter from an in-depthexamination of the legal foundations, and, ultimately, of the validityitself, of the norms of International Law. It has excluded from theexamination of the formation of International Law the substratum oflegal norms : the beliefs, values, ethics, ideas and human aspirations.Not surprisingly, such attitude has rendered the study of the matterrather arid, uninspiring, circumscribed to the modes or procedureswhereby international norms are formally created 615. Such posturehas reduced the outlook of International Law to that of a merely for-mal legal order. This reductionist outlook, conducive to unsatisfac-tory results, has, however, persisted throughout the last decades,and has had, in my view, harmful consequences, among which theperpetuation of the hermetic outlook of the positivist conception,and the emptying of an international legal order insensible to values,and its incapacity to fulfil social needs.

By the late sixties, for example, J. H. W. Verzijl, after duly distin-guishing between the formal and material “sources” of PublicInternational Law, pondered that it was not possible to examinethe “sources” of Public International Law without recognizing theimportance of natural law for the law of nations (droit des gens),irrespective of whether the content of natural law has an “objective”

177

616. J. H. W. Verzijl, International Law in Historical Perspective, Vol. I,Leyden, Sijthoff, 1968, pp. 1-3.

617. In refusing to take into account the principles which transcend the normsof positive law — irrespective of their being captured by doctrine, or by reason,or by human conscience, or formed “spontaneously” (as propounded by the “his-torical school” — ibid., pp. 7-8) — he yielded to the hermetic outlook of legalpositivism.

618. H. Kelsen, “The Basis of Obligation in International Law”, in Estudiosde Derecho Internacional — Homenaje al Profesor C. Barcía Trelles, Santiagode Compostela, University of Santiago de Compostela, 1958, p. 110.

619. J. L. Brierly, The Basis of Obligation in International Law, Oxford,Clarendon Press, 1958, p. 65.

620. Cf. ibid., pp. 66-67, and cf. also pp. 68-80. And, in his Law of Nations,he limited himself, in a rather unsatisfactory way, to say, tout court, that theanswer to this question was to be found outside the legal order, it being incum-bent upon the philosophy of Law to provide it. He thus withheld himself in themiddle of the road . . . Cf. J. L. Brierly, The Law of Nations, 6th ed., Oxford,Clarendon Press, 1963, p. 54.

existence or emanates from human conscience 616. However, some-what surprisingly, he suddenly interrupted this line of reasoning toaffirm that only the “formal” sources, as procedures of “creation”adopted to that end by a given legal system, ought to be regarded as“sources” of Public International Law 617.

Years earlier, the same posture of mental reservation had alreadymanifested itself in legal doctrine. Contrary to what was affirmed,for example, by Hans Kelsen, that it was not possible to reconciliatethe legal order with the moral order 618, it is my view that humanexperience throughout the twentieth century — marked by so manyadvances in the scientific-technological domain accompanied byunprecedented atrocities — demonstrates that it is not possible toconceive the legal order making abstraction of the moral order.

The assertion by Kelsen was made in his evaluation of a classicstudy by J. L. Brierly, who, like him, sought to examine the basis ofvalidity of the norms of International Law. Brierly came to affirm, inhis study, that the connection between Law and moral was muchmore fundamental than its distinction, and that the ultimate basis ofan international obligation rested on its ethical content 619 ; however,further on, Brierly himself confessed not to know how to conciliatethe individual belief to act in conformity with Law with the “impera-tive” character of this latter 620.

In my understanding, there is not, in fact, how to dissociate theformation of International Law for the aspects pertaining to its ownfoundations. The typically positivist feature of approaching theformation of International Law as from the outlook of the formal


621. E.g., the “law-making activity” of some UN organs (for the realizationof UN purposes) — mainly certain resolutions of the General Assembly — witha bearing on the evolving opinio juris of the international community ;D. P. Verma, “Rethinking about New International Law-Making Process”, 29Indian Journal of International Law (1989), pp. 38, 43-44, 46-47 and 51.

622. A. A. Cançado Trindade, “Reflexiones sobre el Desarraigo comoProblema de Derechos Humanos Frente a la Conciencia Jurídica Universal”, inLa Nueva Dimensión de las Necesidades de Protección del Ser Humano en elInicio del Siglo XXI (eds. A. A. Cançado Trindade and J. Ruiz de Santiago), 3rded., San José, Costa Rica, UNHCR, 2004, pp. 72-73.

“sources” of International Law (listed in Article 38 of the ICJStatute) with emphasis on evidence of State consent — as followedfor years in the case-law of the PCIJ and the ICJ — appears increas-ingly open to challenge. It is the posture resulting from the analyti-cal positivism of the nineteenth century, grounded on legal formal-ism (including its list of “sources”), and making abstraction of themultifaceted, vast and complex process of formation of contempo-rary International Law 621, aiming at facing the new challenges withwhich the international community is confronted, besides fulfillingits new needs and aspirations.

In fact, the reductionist posture of considering only the formal“sources” of International Law has never demonstrated the logical orjuridical impossibility of also taking into account the substratum ofjuridical norms. It simply and dogmatically refuses to do so, withoutexplaining why. On my part, I see no impediment for considering, inthe study of the formation of International Law, likewise its material“source”, even if this latter transcends, as it effectively does, thepositive legal order. And I go further : bearing in mind the hardhuman experience accumulated in the last decades, and the newchallenges faced by humankind, I do not see how not to take intoaccount the material “source” of International Law. After all, Inter-national Law is absolutely not at all reduced to an instrument atthe service of power ; its final addressees are ultimately the humanbeings, it being incumbent upon itself to fulfil their needs, amongwhich the realization of justice 622. Its material “source” lies inhuman conscience itself.

II. Human Conscience, Recta Ratio and the Universalityof International Law

The history of international human thinking discloses that con-science has always opposed injustice and rebelled against oppres-


623. Cf., e.g., P. Hazard, La crise de la conscience européenne (1680-1715),Vol. I, Paris, Gallimard, 1968, p. 114.

624. P. Hazard, La crise de la conscience européenne (1680-1715), Vol. II,Paris, Gallimard, 1968, p. 123. As the author pointed out, in the period 1680-1715, even then there was some awareness of the need to unmask the “myth” ofthe overriding, if not unlimited, scientific and material progress (divorced frommoral progress) ; ibid., Vol. II, p. 123.

625. Cf. I. Berlin, The Crooked Timber of Humanity, Princeton, UniversityPress, 1997, pp. 19 and 175.

626. I. Berlin, The Proper Study of Mankind, New York, FSG, 2000, pp. 217,235-236 and 326-358.

627. P. Hazard, op. cit. supra footnote 624, Vol. II, pp. 55 and 71.628. Cf. Chap. I, supra.629. Paraphrasing St. Augustine (Book XI of his Confessions) :

“Qu’est-ce donc que le temps ? Si personne ne me le demande, je le sais.Si quelqu’un pose la question et que je veuille l’expliquer, je ne sais plus.Toutefois, j’affirme avec force ceci : si rien ne passait, il n’y aurait pas depassé ; si rien n’advenait, il n’y aurait pas de futur ; si rien n’était, il n’yaurait pas de présent.” (St. Augustin, Œuvres I — Les Confessionsprécédées de Dialogues philosophiques, Paris, Gallimard, 1998, p. 1041. )

sion 623. In modern history, even before the industrial revolution,there were those who refused to adhere to the growing belief thatscientific and material progress would replace philosophy andhumanities, and “all the demands of the human spirit” 624. The needof the prevalence of the recta ratio has been pointed out in face ofthe considerable sufferings inflicted upon human beings 625 as well asof the divorce between sciences and humanities 626. The rights ofhumanity (droits de l’humanité) were at times invoked already in theseventeenth century and beginning of the eighteenth century 627.

In fact, the notion of conscience is deeply rooted in human think-ing. It marked its presence in classic Greek-Latin thinking, whichfirst attempted to elaborate on it. It might be argued that, born inclassic Greek-Latin thinking, the notion of conscience would be ofdifficult apprehension, as new meanings may be ascribed to itthroughout the centuries. This does not mean that it does not exist ;quite on the contrary, it is always present. The same may be said ofthe very conception of the law of nations, or indeed of any object ofhuman knowledge. While it is true that ideas and conceptions evolvewith time, and so does Law itself (including jus gentium) 628, thisdoes not deprive, in my understanding, the notion of conscience ofan irreducible minimum. Conscience seems to be like time, in thesense that one knows what it means, but if someone asks what it is,one has difficulties in defining it 629.

This irreducible minimum, hardly susceptible of one sole defi-


630. An approximation, e.g., to the practical syllogism of Aristotle. In hisNicomachean Ethics (circa 335-322 BC), Aristotle insists on human behaviour inaccordance with the recta ratio, this being a general principle, valid for all ;Aristóteles, Etica Nicomaquea — Política, Mexico, Ed. Porrúa, 2000, pp. 9, 16,19, 23, 43, 95 and 144 (Book I, Sections VII and XIII ; Book II, Sections II andVI ; Book III, Section XII ; Book VII, Sections VIII and IX ; and Book X,Section IX). Even before him, the recta opinio marks presence in Plato’sDialogues (explicitly in The Banquet) ; cf. Platón, Diálogos, Vol. III (Phedon,The Banquet, Phedro), Madrid, Ed. Gredos, 1997, p. 245.

631. In his De Legibus (On the Laws, circa 51-43 BC, book II), M. T. Ciceroheld that what is “right and true” is also “eternal”, not deriving from legislationand legal decisions ; cf. Cicero, On the Commonwealth and On the Laws (ed. J.E. G. Zetzel), Cambridge, University Press, 2003 (re-ed.), p. 133. Still in his DeLegibus (Book I), Cicero maintained that the whole humankind was “boundtogether”, and “the right way of life” makes “all people better” ; ibid., p. 116. Inhis On Duties (De Officiis, 44 BC), Cicero wrote that “everything produced onthe earth is created for the use of mankind, and men are born for the sake ofmen, so that they may be able to assist one another” ; Cicero, On Duties (eds.M. T. Griffin and E. M. Atkins), Cambridge, University Press, 2003 (re-ed.), p. 10.And in his De Republica (circa late 50s-46 BC), Cicero concentrated on firstprinciples, legitimacy and justice, resorting to natural law ; to him, justice gives“everyone his due”, takes “thought for the interests of mankind”, sparing allhuman beings ; Cicero, The Republic — The Laws, Oxford, University Press,1998, p. 66 (Book III, para. 24).

632. In the first years of our era (up to the year of 63), Seneca’s Letters toLucilius contain passages in which he referred to the “common law ofhumankind” (L. A. Seneca, Cartas a Lucilio (ed. V. López Soto), Barcelona, ed.Juventud, 1982, pp. 124 and 282, and cf. pp. 168 and 375) and affirmed thatvirtue is identified with recta ratio (ibid., p. 177) ; and cf. Sénèque, Entretiens —Lettres à Lucilius (ed. P. Veyne), Paris, Ed. R. Laffont, 1993, pp. 768 and 813).

633. In the thirteenth century, in his Summa Theologiae (Part I), ThomasAquinas wrote that human laws only have the quality of law when they accordwith right reason, and its validity depends upon its justice ; and to be just, lawsought to accord with the rule of reason (a precept of natural law). Cf. relevantexcerpts in Aquinas Selected Political Writings (ed. A. P. D’Entrèves), Oxford,Blackwell, 1970, pp. 121, 125 and 129 ; and cf. Chap. I, supra, footnotes 27-28.

634. Cf. Francisco de Vitoria, Political Writings (eds. A. Pagden andJ. Lawrance), Cambridge, University Press, 1991, pp. XIV-XV.

635. As set forth particularly in his Metaphysic of Morals (Fondements de lamétaphysique des mœurs, 1785), which in Kant’s conception was an a priori,pointing towards the universalization of norms, to the effect of treating humanbeings not as means, but each one as an end in himself, honouring thereby thedignity of human personality. In addition, in his Critique of Practical Reason(1786), Kant conceptualizes conscience as the “internal tribunal” of each personas a “moral being” ; I. Kant, [Critique de] la raison pratique, Paris, PUF, 1963(re-ed.), p. 201.

nition, is always present in the distinct meanings attributed toconscience in the history of human thinking. One may call it“syneidesis/synderesis” (as in ancient Greece 630), or the moralgood (Cicero 631 and Seneca 632), or the knowledge and pursuance ofthe common good (Thomas Aquinas 633), or the precept of rightreason and enlightenment (Francisco de Vitoria 634), or the categoricalimperative (I. Kant 635) — the irreducible meaning is always present,


636. G. Fourlanos, Sovereignty and the Ingress of Aliens, Stockholm, Almqvist& Wiksell, 1986, p. 17, and cf. pp. 19-23, 79-81, 160-161 and 174-175.

corresponding to the recta ratio of the founding fathers of Inter-national Law (as found in Francisco de Vitoria’s De Lege, FranciscoSuárez’s De Legibus, Hugo Grotius’s De Jure Belli ac Pacis), whichappears in fact as the ultima ratio.

The lack or absence of the recta ratio leads to the total submissionof human beings to power-holders, to oppressions and atrocitiesagainst human beings (epitomized by the holocaust and other geno-cides of the twentieth century), and ultimately, to chaos. With therecta ratio of classic international legal thinking the belief comes toprevail that it is possible to capture the contents of the jus gentiumby human reason 636. Such recta ratio does not fall into subjectivism,as it presupposes and calls for an objective International Law,endowed with an intrinsic validity of its own, which renders itcapable of keeping humankind together, united. It further presupposesand calls for an order of universal values, which finds expression inthe universalist outlook of the law of nations, the International Lawfor humankind. Human conscience — more precisely the universaljuridical conscience — appears as the ultimate material source ofInternational Law, providing the intrinsic foundation of jus gentium,in pursuit of the realization of justice.

It goes without saying that, in the historical process of its forma-tion, the law of nations has benefited from contributions of distinctlines of thinking, especially modern International Law in a multi-cultural world. It would be inaccurate not to acknowledge the influ-ence of European history in the origin of the discipline which cameto be known as International Law — in particular the internationallegal order as historically emerged in the Peace of Wesphalia in themid-seventeenth century —, just as it would be likewise inaccuratenot to acknowledge the process of universalization and of humani-zation of International Law that has been gradually taking place formore than a century, with greater intensity in the last decades, withcontributions from distinct cultures.

It is nowadays generally acknowledged that the universality ofInternational Law can recognizedly be achieved only on the basis ofpluralism, mutual respect for cultural diversity, and the pursuance ofcommon aims, converging ultimately into the welfare of humankind.International Law has indeed undergone a process of continuing


637. Cit. in S. Sucharitkul, “L’humanité en tant qu’élément contribuant audéveloppement progressif du droit international contemporain”, in L’avenir dudroit international dans un monde multiculturel/The Future of International Lawin a Multicultural World (colloque de La Haye, novembre 1983, ed. R.-J.Dupuy), The Hague, Nijhoff, Académie de droit international de La Haye/UNU,1984, pp. 418-419.

638. S. Sucharitkul, op. cit. supra footnote 637, pp. 423 and 426-427.

expansion and universalization in a multicultural world, so as to ful-fil the aspirations of humankind. It is my view that there is, in themulticultural world of our times, an irreducible minimum, which, inso far as international law-making is concerned, rests on its ultimatematerial source : human conscience. This may admittedly have dis-tinct forms of expression, in distinct cultures, but I believe they allmean, ultimately, that which is common to all human beings (anddistinguishes them from other species), which guides their actions,which identifies their values, which assists them in searching themeaning of their lives, individually and in socially organized collec-tivities : human conscience.

It is, ultimately, from this latter, however it may be called indistinct parts of the world, that International Law, like all law,emanates. The acknowledgment of the universal juridical conscienceas its ultimate material source (largely overlooked by internationallegal doctrine in recent decades) has likewise taken place, for a longtime already, in lucid writing in distinct parts of the world and indifferent cultures. Thus, in the last quarter of the nineteenth century,for example, Chao Phya Aphay Raja (then main adviser to KingRama V of Thailand), to whom the “expression of public conscience”was the first manifestation of International Law, stated in 1886 that

“Aujourd’hui déjà, les progrès de la conscience publiquenous permettent d’affirmer comme une vérité incontestable quele développement et, par conséquent, la liberté rationnelle del’être humain forment le but principal et légitime de tout droit,national ou international.” 637

One decade later, in a similar line of reasoning, S. Sucharitkulpondered in 1983 that International Law

“devrait être humanisé, aussi longtemps que l’on garde l’espoirde survivre . . .

L’humanité tout entière devrait se faire valoir comme sujet dedroit dans ce monde . . . multiculturel. . . . Si . . . l’homme per-siste dans sa prudence, l’humanité aura encore sa chance.” 638


639. Cf., e.g., M. Koskenniemi, From Apology to Utopia — The Structure ofInternational Legal Argument, Helsinki, Finnish Lawyers’ Publ. Co., 1989,pp. 82, 92, 95, 97, 113, 120, 182 and 357-358.

640. Due to a large extent to the approach of the German historical school oflaw (cf. ibid., p. 367), and the decay of the old positivist dogma of consent (indi-vidual voluntas) to establish international custom ; A. Carty, The Decay ofInternational Law ? A Reappraisal of the Limits of Legal Imagination inInternational Affairs, Manchester, University Press, 1986, pp. 26-28 and 33.Already by the end of the nineteenth century customary law was referred toas “the manifestation of the international juridical conscience” (by the Swissjurist A. Rivier, in his Principes du droit des gens, of 1896), operated by thecontinuous repetition of acts with the awareness of their necessity ; cit. in ibid.,p. 27.

641. Cf., e.g., G. Tassitch, “La conscience juridique internationale”, 65RCADI (1938), pp. 310-311, 314, 316-317 and 320.

In sum, it is human conscience that can lead to, and secure, theuniversality of International Law. The universal juridical conscienceis the material source par excellence of the corpus juris ofInternational Law, which nowadays orients itself to the fulfilment ofthe needs and aspirations of humankind as a whole.

III. The Material Source of International Lawbeyond State Legal Positivism

Throughout the history of international legal thinking, resort to“conscience” and “consciousness” has been much more frequentthan one may prima facie assume. From Grotius to Vattel, fromMartens to Alejandro Álvarez and Barile, the doctrine of Interna-tional Law is replenished with invocations to human conscience toestablish the foundations of the discipline and the validity of itsrules 639. The notion of universal juridical conscience has graduallyfound expression in the theory and practice of International Law,particularly in the last two centuries, with the emergence, in the nine-teenth century, of the concept of communis opinio juris, and itsinsertion into the international legal thinking 640.

In the first decades of the twentieth century, the expression “inter-national juridical conscience” was used, recalling the classic notionof civitas maxima gentium, in order to foster the spirit of interna-tional solidarity 641. In fact, as early as the beginning of the twentiethcentury, as from 1906, Hugo Krabbe propounded a universal legalorder for the whole of humankind, following the Spanish theo-logians’ tradition of International Law ; but unlike F. Vitoria andF. Suárez, who based their construction upon natural law, that of


642. A. Verdross, “Coïncidences : Deux théories du droit des gens apparues àl’époque de la création de l’Académie de droit international”, in HagueAcademy of International Law, Livre jubilaire/Jubilee Book (1923-1973, ed.R.-J. Dupuy), Leyden, Sijthoff, 1973, pp. 84-85.

643. Ibid., p. 85.644. Ibid., p. 92 ; and A. Verdross, “Les principes généraux du droit dans la

jurisprudence internationale”, 52 RCADI (1935), pp. 223 ff.645. A. Verdross, “Coïncidences : Deux théories du droit des gens . . .”,

op. cit. supra footnote 642, p. 93. 646. Ibid., p. 96.

H. Krabbe ensued from the “universal juridical conscience” 642.Léon Duguit, in his turn, envisaged an objective International Lawderiving, not from the sovereignty of States, but rather, again,from “an international juridical conscience” ; his intellectual suc-cessor, Georges Scelle, supported the primacy of International Lawover the various national legal systems 643.

In his account of this doctrinal development, Alfred Verdross heldthat the general principles of law, which lay at the basis of thedomestic law of several nations, were as such recognized bythe “universal juridical conscience” 644. Thus, in the words ofA. Verdross,

“la règle juridique est créée par une pratique constante tandisque[, dans le premier cas,] le principe général naît déjà aumoment de sa première reconnaissance par la consciencejuridique universelle” 645.

All States, whether they have accepted or not the compulsory juris-diction of international tribunals, are bound by such principlesapprehended by the universal juridical conscience 646.

This conceptual evolution was taken further by moving from aninternational into a truly universal dimension. Concern for securingState sovereignty has yielded to concern for jointly guaranteeing theinternational legal order on the basis of a sense of objective justice :the overcoming of the voluntarist conception of International Law(incapable of explaining the process of formation of the norms ofgeneral International Law) was clearly shown by the line of jurispru-dential evolution separating, for example, the obiter dicta of thePermanent Court of International Justice (PCIJ) in the Lotus case(1927) from those of the International Court of Justice (ICJ) in theNorth Sea Continental Shelf cases (1969) ; the acknowledgment ofobjective values much contributed to the formation of the communis


647. B. Stern, “La coutume au cœur du droit international — Quelquesréflexions”, in Mélanges offerts à P. Reuter — Le droit international : unité etdiversité, Paris, Pedone, 1981, pp. 493, 496 and 487 ; Maarten Bos, A Methodo-logy of International Law, Amsterdam, North-Holland, 1984, p. 251, and cf.pp. 246 and 253-255.

opinio juris 647, and the same can be said of the widespread aware-ness of the imperative of fulfilment of the basic social needs of theinternational community as a whole.

To positivists and political “realists”, resort to the universal juridi-cal conscience may appear somewhat difficult to demonstrate, if notmetajuridical. They have, accordingly, sought support for their ownviews mainly in the “will” of States. They seem indifferent torecourse to conscience, which aimed at setting up necessary limitsand controls to the arbitrariness in the “will” of States. This is over-looked by them. They seem likewise oblivious of the fact thatrecourse to conscience has, behind itself, a long-standing juridicalthinking, which, by their insistence on propounding “realism” —which appears en vogue again —, seems almost forgotten in ourdays.

The recourse so commonly and uncritically made nowadays to theallegedly “creative will” of States neglects the fact that the practiceensuing therefrom is not at all devoid of ambiguities, incongruenciesand contradictions. The creative role of the universal juridical con-science in pursuance of common goals of the international com-munity is, in turn, clearly demonstrable. It has been consistentlyinvoked in the theory and practice of International Law: in the elabo-ration adopted texts of international treaties, in the proceedingsbefore international tribunals and in international case-law, and inthe works of international legal doctrine. The universal juridical con-science is, ultimately, the material source of International Law.

IV. Invocation and Assertion of Juridical Conscience inInternational Treaties

In international practice, the idea of a universal juridical con-science has marked presence in many debates of the United Nations(above all of the Sixth Committee of the General Assembly, cf.infra), in the work of the Conferences of codification ofInternational Law (the so-called “law of Vienna”) and in the respec-tive travaux préparatoires of the UN International Law Commission


648. More recently, it has occupied an important space in the cycle of WorldConferences of the United Nations in the nineties ; cf. Chap. XXVI, RCADI,Vol. 317 (2005).

649. United Nations, United Nations Conference on the Law of Treaties —Official Records (UNCLT — OR) (First Session, March/May 1968), Vol. I (state-ment of 4.5.1968), p. 294, para. 7 (emphasis added).

(ILC) 648. References to conscience, certainly susceptible in our daysof a deeper conceptual development, appear likewise in other inter-national treaties. The 1948 Convention against Genocide, forexample, refers, in its preamble, to the “spirit” of the United Nations.Half a century later, the preamble of the Rome Statute of 1998 of theInternational Criminal Court refers to the “conscience of humanity”(second considerandum). And the preamble of the 1994 Inter-American Convention on Forced Disappearance of Persons, to quoteanother example, evokes the “conscience of the hemisphere” (thirdconsiderandum of the preamble).

Other examples can be added. The constitutive elements of theMartens clause — “the principles of humanity and the dictates ofthe public conscience” — are expressly invoked in the preambles ofthe 1977 Additional Protocol II to the 1949 Geneva Conventions onInternational Humanitarian Law (fourth considerandum), and of the1980 Convention on Prohibitions or Restrictions on the Use ofCertain Conventional Weapons (fifth considerandum). Likewise, the1972 Convention on the Prohibition of Bacteriological (Biological)Weapons and on Their Destruction states in the last two con-sideranda of its preamble that the prohibition of those weapons is tothe benefit of all mankind, and that their use “would be repugnant tothe conscience of mankind”.

The universal juridical conscience has been in fact invoked in thetravaux préparatoires of the two Vienna Conventions on the Law ofTreaties (1969 and 1986), by Delegations from different parts of theworld. Thus, in the Vienna Conference of 1968-1969, which adoptedthe 1969 Vienna Convention on the Law of Treaties, the Delegate ofMexico (E. Suárez) stated that

“the rules of jus cogens were those rules which derived fromprinciples that the legal conscience of mankind deemed abso-lutely essential to coexistence in the international community ata given stage of its historical development” 649.

In the same line, the Representative of Italy (A. Maresca) affirmedthat the norms of jus cogens


650. United Nations, UNCLT — OR (Second Session, April/May 1969),Vol. II (statement of 12.5.1969), p. 104, para. 39 (emphasis added).

651. United Nations, UNCLT — OR (First Session, March/May 1968), Vol. I(statement of 6.5.1968), p. 309, para. 32 (emphasis added).

652. Ibid., Vol. I (statement of 7.5.1968), p. 327, para. 74 (emphasis added).653. Ibid., Vol. I (statement of 4.5.1968), p. 296, para. 23 (emphasis added).654. Ibid., Vol. I (statement of 6.5.1968), p. 303, para. 48 (emphasis added).655. United Nations, UNCLT — OR (Second Session, April/May 1969),

Vol. II (statement of 14.5.1969), p. 124, para. 72 (emphasis added).656. United Nations, UNCLT — OR (First Session, March/May 1968), Vol. I

(statement of 6.5.1968), p. 302, para. 33 (emphasis added).657. Ibid., Vol. I (statement of 6.5.1968), p. 301, para. 26 (emphasis added).

“were norms of general International Law acknowledged by theinternational community as a whole, that was to say they werebased on the legal conscience of the whole of mankind” 650.

Likewise, the Delegate of France (J.-J. de Bresson) asserted that

“the substance of jus cogens was what represented the un-deniable expression of the universal conscience, the commondenominator of what men of all nationalities regarded as sacro-sanct, namely, respect for and protection of the rights of thehuman person” 651.

To the Representative of Mali (D. Maiga), also, “the jus cogens rulewould help to strengthen the legal conscience of the nations” 652. TheDelegate of Iraq (M. K. Yasseen), in his turn, warned that

“States could not, by treaty, override those higher norms whichwere essential to the life of the international community andwere deeply rooted in the conscience of mankind” 653.

The Representative of Uruguay (E. Jiménez de Aréchaga) venturedto predict that, in practice, a treaty in breach of those higher norms,amounting to “a flagrant challenge to the international conscience,would be infrequent” 654.

Still in the context of the debates on jus cogens, the Delegate ofSpain (F. de Castro) saw it fit also to warn that international court orarbitrators “could not regard as binding any provision which rancounter to the conscience of the international community” 655. To theRepresentative of Poland (S. Nahlik), the basis of contemporaryInternational Law was to be found in the realities of international lifeas expressed in the “conscience” of States 656. And the Delegate ofColombia (H. Ruiz Varela), likewise, invoked “the rules of the uni-versal legal conscience” 657.


658. United Nations, United Nations Conference on the Law of Treatiesbetween States and International Organizations or between International Orga-nizations — Official Records, Vol. I (statement of 12.03.1986), pp. 187-188,para. 18.

659. In ibid., p. 193, para. 84.660. S. Sucharitkul, “Evolution continue d’une notion nouvelle : le patri-

moine commun de l’humanité”, in International Law at a Time of Perplexity —Essays in Honour of S. Rosenne (ed. Y. Dinstein), Dordrecht, Nijhoff, 1989,p. 905.

It should not pass unnoticed that, already by the late sixties, in thetwentieth century, such invocations of the universal juridical con-science, as related to the peremptory norms of International Law,came from Delegates of all latitudes and distinct juridical and cul-tural backgrounds. They echoed the pluralist international commu-nity of those days, which, notwithstanding, felt the need for theassertion of such universal juridical conscience. Thus, contrary towhat the spokesmen of an outdated positivism try to contend, suchassertion was a reaction to the old pattern of domination or manipu-lation of the international legal order by a small number of indi-vidual big powers, with all the abuses that it entailed.

More recently, in the mid-eighties, the issue was again dwelt uponat the 1986 UN Conference on the Law of Treaties betweenStates and International Organizations or between InternationalOrganizations. On that occasion, the Representative of Brazil (A. A.Cançado Trindade) warned that jus cogens was “incompatible withthe voluntarist conception of International Law, because that concep-tion failed to explain the formation of rules of general InternationalLaw” 658. And the Delegate of Cyprus (Droushiotis) added that“norms of jus cogens were the most important rules of InternationalLaw, as they were of a universal nature and contained obligationserga omnes” 659.

One could hardly deny the tendency of contemporary Interna-tional Law to develop the protection of mankind as a whole — aprocess which has been fostered by decolonization and the emer-gence and development of International Human Rights Law 660. Evenbefore the insertion of the concept of jus cogens in the first ViennaConvention on the Law of Treaties (that of 1969), the Delegations ofsome States related the emerging concept to the universal juridicalconscience, in the course of the debates at the Sixth Committee ofthe UN General Assembly on the Draft Articles by the ILC on theLaw of Treaties.


661. Cit. in M. Pérez González, “Los Gobiernos y el Jus Cogens : LasNormas Imperativas del Derecho Internacional en la Sexta Comisión”, inEstudios de Derecho Internacional Público y Privado — Homenaje al ProfesorL. Sela Sampil, Vol. I, Universidad de Oviedo, 1970, pp. 107 and 109.

662. Cit. in ibid., pp. 118 and 115, respectively. The modifications introducedby the jus cogens superveniens were regarded as being due to a change in the“communitarian conscience” as to the application of international norms ; ibid.,p. 115.

Thus, as indicated by a study on this specific point, in thosedebates (of 1963-1966) of the Sixth Committee, prior to the adoptionof the 1969 Vienna Convention, the Delegations of some Statesrelated the foundations of jus cogens to the superior interests, thevery maintenance and survival of the international community. Thus,the Delegation of Cyprus, for example, stated that certain norms findtheir essential justification as being “the common expression of theconscience of the international community” 661. To the FrenchDelegation, the universal character of jus cogens indicated that cer-tain principles were binding upon the international community as awhole, while the Italian Delegation, in its turn, identified in this newtrend an evolution towards a “true universal public law” 662.

V. Universal Juridical Conscience : The Historical Significanceof the Martens Clause

A clause of major transcendence deserves to be singled out : theso-called Martens clause, which counts on more than a century ofhistory. Presented by the Delegate of Russia (Friedrich von Martens)to the I Hague Peace Conference (of 1899), it was inserted into thepreambles of the II Hague Convention of 1899 (para. 9) and of theIV Hague Convention of 1907 (para. 8), both pertaining to the lawsand customs of land warfare. Its purpose — pursuant to the wise pre-monition of the Russian jurist and diplomat — was to extend juridi-cally the protection to civilians and combatants in all situations, eventhough not contemplated by the conventional norms ; to that end, theMartens clause invokes “the principles of International Law” derivedfrom “established custom”, as well as “the principles of humanity”and the “dictates of public conscience”. Subsequently, the Martensclause was again to appear in the common provision, concerningdenunciation, of the four Geneva Conventions of InternationalHumanitarian Law of 1949 (Article 63/62/142/158), as well as in theAdditional Protocol I (of 1977) to those Conventions (Art. 1 (2) ) — to


663. B. Zimmermann, “Protocol I — Article 1”, in Commentary on theAdditional Protocols of 1977 to the Geneva Conventions of 1949 (eds. Y. San-doz, Ch. Swinarski and B. Zimmermann), Geneva, ICRC, Nijhoff, 1987, p. 39.

664. H. Meyrowitz, “Réflexions sur le fondement du droit de la guerre”, inEtudes et essais sur le droit international humanitaire et sur les principes de laCroix-Rouge en l’honneur de Jean Pictet (ed. Ch. Swinarski), Geneva, TheHague, CICR, Nijhoff, 1984, pp. 423-424 ; and cf. H. Strebel, “Martens’Clause”, in Encyclopedia of Public International Law (ed. R. Bernhardt), Vol. 3,Amsterdam, North-Holland Publ. Co., 1982, pp. 252-253.

665. F. Münch, “Le rôle du droit spontané”, in Pensamiento Jurídico y Socie-dad Internacional — Libro-Homenaje al Prof. D. A. Truyol Serra, Vol. II,Madrid, Univ. Complutense, 1986, p. 836 ; H. Meyrowitz, op. cit. supra foot-note 664, p. 420.

666. H. Sultan, “La conception islamique du droit international humanitairedans les conflits armés”, 34 Revue égyptienne de droit international (1978),

quote some of the main Conventions of International HumanitarianLaw.

The Martens clause has thus been endowed, throughout more thana century, with continuing validity — in its invocation of public con-science — as, however advanced may the codification of humanitar-ian norms be, it will hardly be considered as being truly complete.The Martens clause thus continues to serve as a warning againstthe assumption that whatever is not expressly prohibited by theConventions on International Humanitarian Law could be allowed ;quite on the contrary, the Martens clause sustains the continuedapplicability of the principles of International Law, the principlesof humanity and the dictates of public conscience, independently ofthe emergence of new situations and of the development of techno-logy 663. The Martens clause impedes, thus, the non liquet, and exertsan important role in the hermeneutics and the application of humani-tarian norms.

The fact that the draftsmen of the Conventions of 1899, 1907 and1949 and of Protocol I of 1977 have reiteratedly asserted theelements of the Martens clause in those international instrumentsreckons that clause as an emanation of the material source ofInternational Humanitarian Law 664 and of International Law in gen-eral. In this way, it exerts a continuous influence in the spontaneousformation of the contents of new rules of International HumanitarianLaw 665. The Egyptian jurist Hamed Sultan, for example, has relatedthe “modern language” of the Martens clause to longstanding fun-damental principles of the Islamic conception of Humanitarian Law(such as those of justice and equity, and of the dignity and integrityof the human person) 666.


pp. 7-9, and cf. p. 4. And cf. also, on the dictates of public conscience in gen-eral, e.g., W. B. Hallaq, The Origins and Evolution of Islamic Law, Cambridge,Cambridge University Press, 2005, p. 203.

667. C. Swinarski, “Préface”, in V. V. Pustogarov, F. F. Martens . . ., op. cit.infra footnote 668, p. xi.

668. V. V. Pustogarov, Fedor Fedorovitch Martens — Jurist i Diplomat,Moscow, ed. Mezdunarodinye Otnoscheniya, 1999, pp. 1-287.

669. F. Münch, op. cit. supra footnote 665, p. 836. 670. S. Miyazaki, “The Martens Clause and International Humanitarian

Law”, in Etudes et essais . . . en l’honneur de J. Pictet, op. cit. supra foot-note 664, pp. 438 and 440.

The Swiss-Polish jurist Christophe Swinarski pondered that, byintertwining the principles of humanity and the dictates of publicconscience, the Martens clause establishes an “organic interdepen-dence” of the legality of protection with its legitimacy, to the benefitof all human beings 667. A monograph published in Russia in 1999 onthe legacy of Martens stressed the primacy of Law in the settlementof disputes and search for peace 668. Contemporary juridical doctrinehas also characterized the Martens clause as source of generalInternational Law itself 669 ; and no one would dare today to denythat the “principles of humanity” and the “dictates of public con-science” invoked by the Martens clause belong to the domain of juscogens 670. The aforementioned clause, as a whole, has beenconceived and reiteratedly affirmed, ultimately, to the benefitof humankind as a whole, thus maintaining its topicality. Theclause may be considered as an expression of the raison d’humanitéimposing limits to the raison d’Etat.

VI. Invocation of Juridical Conscience in Judicial Proceedingsand International Case-Law

In the course of the advisory proceedings (written and oralphases) before the ICJ (1994-1995) pertaining to the requests by theUN General Assembly and the World Health Organization (WHO)for an Advisory Opinion (rendered in 1996) on the question of thelegality (or rather illegality) of nuclear weapons, some of the inter-vening States, not surprisingly, invoked the “principles of humanity”or the “dictates of public conscience” in their arguments. To recallbut a couple of examples, Australia, for example, expressly invokedthe Martens clause, and argued that the principles of humanity andthe dictates of public conscience are not static, and permeate thewhole of International Law in its evolution, calling for the prohibi-


671. ICJ, loc. cit., pleadings of Australia (1995), pp. 45, 60 and 63, and cf.p. 68.

672. Government of Japan, Written Statement of the Government of Japan (onthe Request for an Advisory Opinion to the ICJ by the World HealthOrganization), 10 June 1994, p. 2 (internal circulation) ; Government of Japan,Written Statement of the Government of Japan (on the Request for an AdvisoryOpinion to the ICJ by the United Nations General Assembly), 14 June 1995, p. 1(internal circulation) ; Government of Japan, The Oral Statement by theDelegation of Japan in the Public Sitting Held at the Peace Palace, The Hague,07 November 1995, p. 1 (internal circulation).

673. ICJ, loc. cit., pleadings of New Zealand (1995), p. 33.674. ICJ, loc. cit., pleadings of Egypt (1995), pp. 37-41 and 44.675. Express references to the universal juridical conscience are found, e.g.,

in some of my Individual Opinions in the case-law of the IACtHR, e.g., inAdvisory Opinion No. 16, on the Right to Information on Consular Assistance inthe Ambit of the Guarantees of the Due Process of Law (1999), paras. 3-4, 12and 14 ; in the Provisional Measures of Protection in the case of the Haitiansand Dominicans of Haitian Origin in the Dominican Republic (2000), para. 12 ;in the case Bámaca Velásquez versus Guatemala (Merits, Judgment of 25 No-vember 2000), paras. 16 and 28, among others.

tion of nuclear weapons for all States. Australia further recalled thefinal preambular paragraph of the Convention against BiologicalWeapons, pondering that its warning that those weapons are “repug-nant to the conscience of mankind” applies likewise to nuclearweapons, and that the use of them all would be contrary to generalprinciples of humanity 671.

In its turn, Japan contended that the use of nuclear weapons, forthe considerable injuries inflicted, was clearly contrary to the prin-ciple of humanity in the foundation of International Law 672. NewZealand stated that the rationale of the 1968 Nuclear Non-Proliferation Treaty is that “nuclear weapons are too dangerous forhumanity and must be eliminated” 673. And Egypt asserted that thethreat or use of nuclear weapons as weapons of mass destructionis prohibited by International Humanitarian Law ; the AdditionalProtocol I of 1977 to the 1949 Geneva Conventions establishes theprohibition of unnecessary suffering (Art. 35) and imposes the dif-ferentiation between civilian population and military personnel(Art. 48). Thus, by their effects, nuclear weapons, being weapons ofindiscriminate mass destruction, infringe International HumanitarianLaw, which contain precepts of jus cogens, as recalled by successiveresolutions of the UN General Assembly ; those precepts are theopinio juris of the international community 674.

As to international case-law, a prompt example lies in the case-law of the Inter-American Court of Human Rights (IACtHR) 675, towhich one may add the emerging case-law of the two ad hoc Inter-


676. Cf., e.g., A. A. Cançado Trindade, “La jurisprudence de la Cour interna-tionale de Justice sur les droits intangibles/The Case-Law of the InternationalCourt of Justice on Non-Derogable Rights”, in Droits intangibles et états d’ex-ception/Non-Derogable Rights and States of Emergency (eds. D. Prémont,C. Stenersen and I. Oseredczuk), Brussels, Bruylant, 1996, pp. 73-89 ; and cf.Chap. XVI, RCADI, Vol. 317 (2005).

677. A. Carty, op. cit. supra footnote 640, pp. 26-28 and 33.678. Cf., e.g., G. Tassitch, “La conscience juridique internationale”, op. cit.

supra footnote 641, pp. 310-311, 314, 316-317 and 320.679. Cf. Annuaire de l’Institut de droit international (New York Session),

Vol. II, 1929, pp. 114, 134-135 and 137.

national Criminal Tribunals, for the former Yugoslavia and Rwanda.And the case-law itself of the ICJ contains elements developed asfrom, for example, basic considerations of humanity 676.

VII. Invocation and Assertion of Juridical Consciencein International Legal Doctrine

Also in the doctrine of International Law elements are found forthe development of the matter, although, surprisingly, not suffi-ciently articulated to date. The notion which I see it fit to denomi-nate universal juridical conscience comes to find doctrinal expres-sion in relatively recent times (cf. supra), particularly throughout thetwentieth century, with the emergence of the concept of communisopinio juris, to face the old positivist dogma of individual consent(voluntas) for the formation of customary law 677. In the first threedecades of the twentieth century, the expression “international juridi-cal conscience” was effectively utilized, in a slightly distinct sense,recalling the classic notion of civitas maxima, so as to promote andfoster the spirit of international solidarity 678.

The debates of the Institut de Droit International (New YorkSession of 1929) about a project of declaration on human rightsmay here be recalled. It was observed, on the occasion, that the“spiritual life” and the “juridical conscience” of the peoples requireda new law of nations, with the affirmation of human rights 679. At agiven moment of those memorable debates of 1929 of the Institut— almost forgotten in our days — it was pondered, for example,that

“dans la conscience du monde moderne, la souveraineté de tous lesEtats doit être limitée par le but commun de l’humanité. . . . L’Etatdans le monde n’est qu’un moyen en vue d’une fin, la perfectionde l’humanité . . . La protection des droits de l’homme est le devoir


680. Op. cit. supra footnote 679, pp. 112 and 117.681. Cit. in ibid., p. 298.682. To him, “international justice” itself emanates from the “public con-

science” or “conscience of the peoples” ; A. Álvarez, La Reconstrucción delDerecho de Gentes — El Nuevo Órden y la Renovación Social, Santiago deChile, ed. Nascimento, 1944, pp. 19-21, 24-25 and 86-87, and cf. p. 488.

683. A. Álvarez, “Méthodes de la codification du droit international public —Rapport”, in Annuaire de l’Institut de droit international (1947) pp. 38 and 46-47, and cf. pp. 50-51, 54, 64 and 69.

684. Ibid., pp. 44-45 and 68-69, and cf. p. 70.685. B. V. A. Röling, International Law in an Expanded World, Amsterdam,

Djambatan, 1960, pp. xiii, xv, 52-53, 56, 83, 122 and 126. Such goals — headded — were prompted by a “revolt” of international conscience against thehorrors (in particular the criminal Nazi practices) of World War II, and a new

de tout Etat envers la communauté internationale. . . . Il s’agit deproclamer les droits que la conscience du monde civilisé reconnaîtaux individus en tant qu’hommes . . .” 680

At the end of the debates referred to, the Institut (22nd Commission)in fact adopted a resolution containing the “Déclaration des droitsinternationaux de l’homme”, the first considerandum of whichemphatically affirmed that “the juridical conscience of the civilizedworld requires the recognition to the individual of rights safeguardedfrom any threat or breach on the part of the State” 681.

Still at the time of World War II (1944), Alejandro Álvarez sus-tained that the principles of law and the precepts of internationaljustice emanated spontaneously from the international juridical con-science 682. And, three years later, in a report submitted to the Institutde Droit International (1947 Lausanne session), A. Álvarez, amidstthe “grave crisis” faced by International Law, reiterated his view thatinternational justice was a manifestation of the international juridicalconscience, to which the precepts of the law of nations owed theirformation 683 ; he added that the general interests of the internationalcommunity should “model” the “rights of States and individuals”and guide the work of reconstruction of International Law 684.

On his part, in his inspiring monograph International Law in anExpanded World (1960), B. V. A. Röling also invoked the superiorinterests of the international community as a whole to protecthumankind against war, to “protect the weak against the strong”, toestablish an international legal order in which members are “legallyobliged to abstain from actions unreasonably harmful to others”, andto lay the basis — in an expanded world — for the construction of atruly universal International Law 685. Further references to the “juridi-


awareness that human beings could no longer be left entirely only as subjects oftheir respective nation-States (ibid., p. 114) ; their rights emanated directly fromInternational Law.

686. A. Gómez Robledo, Meditación sobre la Justicia, Mexico, BuenosAires, Fondo de Cultura Económica, 1963, pp. 179 and 185.

687. S. Glaser, L’arme nucléaire à la lumière du droit international, Paris,Pedone, 1964, p. 18.

688. Maarten Bos, A Methodology . . ., op. cit. supra footnote 647, 1984,p. 251, and cf. pp. 246 and 253-255.

689. B. Stern, “La coutume au cœur . . .”, op. cit. supra footnote 647,p. 487.

690. T. O. Elias, “Modern Sources of International Law”, in TransnationalLaw in a Changing Society : Essays in Honour of Ph. C. Jessup (eds. W.Friedmann, L. Henkin and O. Lissitzyn), New York, London, Columbia Univer-sity Press, 1972, p. 51.

cal conscience” and “moral conscience” are found, for example, inthe Meditación sobre la Justicia (1963) of Antonio Gómez Robledo,amidst his lucid criticism of legal positivism 686. Still in the mid-sixties, S. Glaser sustained that customary international norms arethose that, “according to universal conscience”, ought to regulatethe international community, for fulfilling common interest andresponding to the demands of justice ; and he added that

“C’est sur cette conscience universelle que repose la princi-pale caractéristique du droit international : la conviction que sesnormes sont indispensables pour le bien commun explique leurreconnaissance en tant que règles obligatoires.” 687

The recognition of certain fundamental values, embodying a senseof objective justice, has much contributed to the ongoing evolutionof the communis opinio juris 688 in the last decades of the twentiethcentury. One acknowledges here a conceptual evolution which hasmoved, as from the sixties, from the international to the universaldimension (under the great influence of the development of theInternational Law of Human Rights itself), conducive to the identifi-cation of the common interests of the international community andof the generalized recognition of the imperative to satisfy basichuman needs 689. Thus, in the early seventies, it was possible tobehold — as done by the Nigerian jurist T. O. Elias, for example —an “overwhelming trend toward consensus which is an expression ofthe juridical conscience of the world community” 690.

Later on, in the late eighties, a trend of the international legal doc-trine asserted that the source of the higher norms of InternationalLaw lies in the universal conscience, wherefrom certain principles of


691. G. Sperduti, “La souveraineté, le droit international et la sauvegarde desdroits de la personne”, in International Law at a Time of Perplexity — Essays inHonour of S. Rosenne, Dordrecht, Nijhoff, 1989, pp. 884-885, and cf. p. 880 ; headded that the jurist must tell the truth, beyond positivism, which is illogical(ibid., pp. 879-880).

692. Cf. Chap. III, supra.

International Law also emanate ; positivist doctrine proved incapableof elaborating a conception of International Law conducive to estab-lishing a true legal order, it thus becoming necessary to identify inthe “universal conscience” the ultimate source of the “supremenorms of International Law” 691. These are but some examples todisclose that, throughout the twentieth century, there were jusinter-nationalists who had the intuition and sensitiveness to detect thereality of human conscience, beyond the crude “reality” of the facts.

VIII. Final Observations : The Achievements of International Lawand the Universal Juridical Conscience

Throughout the time of formation and growth of International Law,resort to the universal juridical conscience has helped to set necessarylimits to excesses of those who hold public power, whose decisionswere identified as the “will” of the States. This latter has oftenappeared as a disaggregating factor, accounting for incongruenciesand contradictions in State practice. Thus, traditional InternationalLaw, as it stood at the beginning of the last century, was character-ized by unlimited State voluntarism, which was reflected in the per-missiveness of recourse to war, of the celebration of unequal treaties,of secret diplomacy, of the maintenance of colonies and protec-torates and of zones of influence. Against this oligarchical and unjustorder principles arose such as those of the prohibition of the use andthreat of force and of the war of aggression (and of the non-recogni-tion of situations generated therefrom), of the juridical equality ofStates, of the peaceful settlement of international disputes 692. More-over, there started the struggle against inequalities (with the aboli-tion of the capitulations, the establishment of the system of protec-tion of minorities under the League of Nations, and the adoption ofthe first international labour conventions of the ILO).

The universal juridical conscience, unlike the voluntarist concep-tion, has consistently given expression to the fundamental principlesof International Law. The invocation of these latter came to fulfil the


693. Cf. A. Truyol y Serra, Fundamentos de Derecho Internacional Público,4th ed., Madrid, Tecnos, 1977, pp. 19, 61, 68, 73, 104-105 and 117.

694. Parallel to that, in the United Nations era the system of collective secu-rity was consolidated, which, however, did not satisfactorily operate as a resultof the deadlocks generated by the cold war — though it remains essential todayfor the preservation of international peace and security.

695. A. A. Cançado Trindade, Direito das Organizações Internacionais, 3rd.ed., Belo Horizonte, Brazil, Edit. Del Rey, 2003, pp. 724-737.

696. United Nations, The Work of the International Law Commission, 5th ed.,New York, United Nations, 1996, pp. 1-501.

“ethical demands” of the international legal order, as from a renewedjusnaturalist outlook. Such principles came to illuminate the forma-tion and evolution of the international legal order, given the flagrantincapacity of legal positivism to explain the formation of customarynorms, of visualizing Law as a means for the realization of justice,and of recognizing that the ultimate foundation of Law is neces-sarily found outside the positive legal order 693.

In the mid-twentieth century the necessity was recognized of thereconstruction of International Law with attention turned to therights inherent in every human being — of what the adoption of theUniversal Declaration of 1948 gave eloquent testimony, followed,over five decades, by more than 70 treaties of protection nowadaysin force at global and regional level 694, in a manifestation of theawakening of the universal juridical conscience to the necessity tosecure the effective protection of the human being in all and any cir-cumstances. International Law came to experience, in the secondhalf of the twentieth century, an extraordinary expansion, fostered ingreat part by the operation of the United Nations and specializedagencies, as well as regional organizations.

Thus, by direct influence of the international organizations, theprocess of formation of the norms of International Law became com-plex and multifaceted, in the purpose of achieving a wide regulationwhich fulfilled the needs and aspirations of the international com-munity as a whole 695. The vast normative production of the UnitedNations, for example, was no longer limited to the projects of theILC 696 — which retain their value and utility — but came to extenditself to the General Assembly, to its Sixth Committee (for LegalAffairs), to the Conferences of Plenipotentiaries convened by theUnited Nations ; furthermore, specialized agencies of the UnitedNations system, such as the International Labour Organization(ILO), UNESCO, the International Atomic Energy Agency (IAEA),among others — besides regional organizations — came to produce


697. A. Pellet, “La formation du droit international dans le cadre des NationsUnies”, 6 European Journal of International Law (1995), pp. 401-425 ; F. Cede,“New Approaches to Law-Making in the U.N. System”, 1 Austrian Review ofInternational and Comparative Law (1996), pp. 51-66 ; E. McWhinney, LesNations Unies et la formation du droit, Paris, Pedone/UNESCO, 1986, pp. 101-129 and 261-287.

698. Cf. H. Valladão, Democratização e Socialização do Direito Interna-cional, Rio de Janeiro, Livr. José Olympio ed., 1961, pp. 7-98 ; P. Buirette-Maurau, La participation du tiers-monde à l’élaboration du droit international,Paris, LGDJ, 1983, pp. 19-202.

699. The United Nations gradually turned their attention also to the economicand social domain, besides international trade, without prejudice to their initialand continued concern with the preservation of international peace and security.

700. In distinct areas such as those of outer space and the law of the sea.701. B. Conforti, “Humanité et renouveau de la production normative”, in

Humanité et droit international — Mélanges R.-J. Dupuy, Paris, Pedone, 1991,pp. 113-114 and 118.

numerous treaties and conventions of importance in distinct areas ofhuman activity 697.

The emergence of new States, in the course of the historical pro-cess of decolonization, was to mark deeply its evolution in the fiftiesand sixties, amidst the great impact within the United Nations of theemerging right of self-determination of peoples. The process ofdemocratization of International Law was launched 698. In transcend-ing the old parameters of the classic law of peace and war,International Law was equipped to respond to the new demandsand challenges of international life, with greater emphasis on inter-national co-operation 699.

In the sixties up to the eighties, multilateral forums were engagedin an intense process of elaboration and adoption of successivetreaties and resolutions of regulation of the spaces 700. From thenonwards International Law has gradually undergone a remarkabletransformation. As accurately observed, contemporary InternationalLaw ceased to be a formalistic legal order, to become a “droitmatériel”, and “under the pressure of the universal human commu-nity . . . the normative production has enriched”, giving expressionto the “values of solidarity and of justice among peoples” 701.

The evolution of International Law throughout the twentiethcentury bears witness of advances due, in my understanding, to theirultimate material “source”, the universal juridical conscience —despite successive abuses committed against human beings andvictimizing humankind as a whole. There are several elements thatdisclose such advances, whether one dwells upon international case-law, or the practice of States and international organizations and


702. A. A. Cançado Trindade, O Direito Internacional em um Mundo emTransformação, Rio de Janeiro, ed. Renovar, 2002, pp. 1039-1109.

703. P. Teilhard de Chardin, Himno del Universo, 2nd ed., Madrid, ed. Trotta,2000 (re-ed.), pp. 90-91.

of other subjects of International Law, or else the more lucidjuridical doctrine. From these elements there ensues — may I insiston this central point — the awakening of a universal juridical con-science, to reconstruct, at this beginning of the twenty-first cen-tury, International Law, on the basis of a new paradigm, no longerState-centric, but rather placing human beings in a central positionand bearing in mind the problems which affect the whole of human-kind 702.

Recourse to the universal juridical conscience has thus been inline with the humanist thinking in International Law, with theacknowledgment of the pressing need to set limits to force in therelations among States and other subjects of International Law. Onthe one hand, resort to “will” is in line with the factual capacity toact and influence of each one of them, which varies from State toState and other subjects of International Law, and favours the pri-macy of authority and force over belief. The former posture, ofrecourse to the universal juridical conscience, supports, in turn, theprimacy of spirit over matter (which is the view I have always firmlysustained).

Throughout the successive crisis and disasters that have affectedhumankind, it has notwithstanding remained aware of its creativityand of the need to be master of its own fate. It is true that humankindhas, in a temporal dimension, witnessed the destruction of civiliza-tions in history, one after another, but it is equally true that it hasremained aware of the importance of conscience to guide humanaction and the evolution of humankind itself. As poignantlyremarked by Pierre Teilhard de Chardin, although Susa, Memphis,Athens, and other centres of civilization, died in their respectiveepochs, yet a “conscience of the universe” has kept on evolving andgrowing throughout time 703.

The destructive forces, both natural disasters and man-made wars,have not succeeded in hindering the course of evolution of thatconscience, and of the awareness of the need to live with justiceand peace in an orderly universe. That conscience is the ultimatematerial source of all Law. It is, after all, not surprising that, despitethe rise and fall of civilizations in time (for example, Rome), the idea


704. Cf. Montesquieu, Considérations sur les causes de la grandeur desRomains et de leur décadence (1734), Paris, Garnier, 1954 (re-ed.), pp. 50-51,62 and 118.

705. Cf. my Concurring Opinion in the Advisory Opinion No. 16, on the Right toInformation on Consular Assistance in the Framework of the Guarantees of the DueProcess of Law (1999), paras. 3-4, 12 and 14 ; Concurring Opinion in the ProvisionalMeasures of Protection in the case of the Haitians and Dominicans of Haitian Originin the Dominican Republic (2000), para. 12 ; Separate Opinion in the BámacaVelásquez versus Guatemala case (Merits, 2000), paras. 28 and 16 ; ConcurringOpinion in the Advisory Opinion No. 18, on the Juridical Condition and Rights ofUndocumented Migrants (2003), paras. 23-25 and 28-30, esp. para. 29.

706. A provision which is 85 years old . . .707. Its addressees are the States, international organizations, peoples and

human beings, and ultimately humankind, and it ought to fulfil their needs,among which and above all the realization of justice.

of Law has survived all destruction 704, has moved forward, in myunderstanding, by human conscience, in pursuit of the realization ofan objective justice.

Over a decade of experience so far, serving as Judge of an inter-national tribunal of human rights, has reinforced my feelings that theuniversal juridical conscience is the material source par excellenceof International Law. In several of my Individual Opinions in thecase-law of the IACtHR I have sustained my understanding that it isdue ultimately to the universal juridical conscience that we can wit-ness nowadays the current historical process of humanization ofInternational Law 705. I sincerely hope that the legal doctrine of thetwenty-first century comes to dedicate considerably more attentionto the material source of International Law, to the foundations andthe validity of the norms of this latter.

The prevailing attitude of international lawyers in the last decadesof the twentieth century was to limit themselves to the “formal”sources of International Law, as recognized in Article 38 of the ICJStatute 706. This provision was a product of its time (1920), and thechallenges of the twenty-first century do require to go much furtherthan that. The study of the “sources” of International Law cannot beappropriately undertaken from a strictly positivist outlook, makingabstraction of the values. International Law 707 cannot at all bereduced to an instrumental at the service of power.

Some may argue, and have argued, that the universal juridicalconscience is metajuridical. If one bears in mind that no norm ofpositive law can become the source of its own validity, then oneneed not fear the charge that the material source of InternationalLaw, like that of any law, is indeed metajuridical, and this in my


708. It may be recalled that, as already pointed out in this General Course —in the process of elaboration of the 1970 UN Declaration on Principles ofInternational Law concerning Friendly Relations and Co-operation amongStates, the understanding was propounded that the Declaration was intended toexpress a “universal juridical conviction” ; cf. Chap. III, supra.

view does not exempt international lawyers from the duty to con-sider it in good faith 708. Jurists of the past (until the seventies)appeared more prepared to go into an examination of the matter, ingreater depth, than most of our contemporaries. Hence the reduc-tionist views of International Law that unfortunately seem to prevailin our days, marked by pragmatism and “technicism”. Many interna-tional lawyers nowadays seldom dare to go beyond positive law,being on the contrary receptive — if not subservient — to relationsof power and dominance, and thus paying a disservice toInternational Law. Jurists cannot make abstraction of the ineluctableaxiological dimension of the discipline, and in my view cannot trulyescape considering its ultimate material source : the universal juridi-cal conscience.

It is this latter that moves ahead International Law, as all Law.The universality of International Law cannot possibly be achievedon the basis of positive law strictly ; nor can an international legalorder turned to the fulfilment of the needs and aspirations ofhumankind. Hence the great necessity, and utmost importance, oftaking into due account, first and foremost, the material source ofInternational Law, and of all Law, that which actually moves it for-ward always : the universal juridical conscience.

In conclusion, the very dynamics of contemporary internationallife, moved by human conscience, has taken care of dismissing thetraditional view that international norms derive entirely from the“free will” of the States themselves. It has evidenced that one couldonly find an answer to the problem of the foundations and validity ofthis latter in the universal juridical conscience, as from the assertionof the idea of an objective justice. At this beginning of the twenty-first century, we have the privilege to witness and the duty to fosterthe process of humanization of International Law, which, in confor-mity with the new ethos of our times, comes to dwell more directlyupon the identification and realization of common superior valuesand goals. In this way, International Law evolves, expands itself,strengthens and improves itself, and, ultimately, legitimates itself.
