Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Basic Criminal Law – The U.S. Constitution, Procedure, and CrimesBy Anniken U. Davenport
CHAPTER 9: COMMON LAW DEFENSES
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Chapter Objectives Know the common law defenses, and
their essential elements Understand the concept of self-defense
and be able to explain when non-deadly and deadly force can be used
Explain under what circumstances consent is a defense
Explain when mistake of law and mistake of fact are defenses
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Chapter Objectives (cont’d)
Explain entrapment Differentiate between the
consequences of voluntary and involuntary intoxication
Explain the different standards for the insanity defense and how each operates
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Sources of Defenses common law constitutional law statutory law
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Justification Defenses Used where the commission of the
proscribed act is justified and, therefore, not appropriate for criminal sanctions.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Self-Defense A justification resting on the belief
that innocent people have the right to protect themselves and their property from crime. Each case is judged differently based
on the facts of that case.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Non-Deadly and Deadly Force
non-deadly force – a person may use a reasonable amount of force to render an attacker harmless
deadly force – a person may only use deadly force in self-defense when it reasonably appears necessary to prevent immediate death or serious injury or prevent the commission of a serious felony involving risk to human life. Deadly force may only be used against an attacker who has initiated the aggression using unlawful force
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
The Retreat Rule Definition – generally, if a person is using
deadly force to stop a crime, he/she should always choose to retreat if the opportunity to do so arises A person must retreat rather than use
deadly force unless the person is at his or her home or business.
Most states have adopted the rule that there is no duty to retreat unless the retreat can be made in complete safety.
The attacker can also use the retreat rule if he/she tried to make a withdrawal but the defender continued to use force.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Doctrine of Sudden Escalation If a fight that was not life
threatening suddenly becomes life threatening, the initial aggressor can take whatever action is necessary to protect himself.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Defense of Others A defendant can use the defense of
others defense when he acts in the belief the intended victim had a legal right to act in his or her own defense. There need not be any special relationship between the defendant and the intended victim. In this case, the defendant need not retreat unless he is sure the victim is safe.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Defense of Property The law recognizes a difference between
defense of self and defense of property. Generally, it is not appropriate to use deadly force to defend objects unless a person is also in immediate danger. Katko v. Briney – the Iowa Supreme Court let
stand a jury verdict for actual and punitive damages against the owner of an abandoned farmhouse who had rigged a rifle to go off if an intruder entered. An intruder did, and sued successfully when he was injured
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Necessity Defense A justification defense that asserts
that it was necessary to break law in order to prevent a more serious crime. The necessity defense can never be used
to justify a death to protect property. To use this defense, the defendant must
be without fault and cannot be in the process of committing another crime at the time the act was committed.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Duress Defense Duress is a defense if the defendant committed
the crime out of a well-grounded fear of death or serious bodily harm.• Required elements for a duress defense:
the actor was wrongfully threatened by another to perform an act that he/she otherwise would not have performed; and
the threat was of serious bodily harm or death to the person or an immediate family member;
the threat was immediate and there was no way for the threatened person to escape or avoid the threatened action;
the harm threatened was greater than the harm from the crime committed; and
the threatened person was not intentionally involved in the situation.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Mistake of Fact Defense Used when a defendant honestly believes
something to be true that is not true. The mistake of fact defense applies to
different crimes differently. For general intent crimes the mistake must be a
reasonable mistake. For specific intent crimes, any mistake of fact may
be used as a defense. You could not form the specific intent to commit a
crime if you are mistaken about the facts. The mistake of fact defense may not be used for
strict liability crimes.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Mistake of Law Defense Used when a person in good faith
relied on an interpretation of law from a person charged with administering the law. The mistaken interpretation of law
may not come from an attorney.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Entrapment Used when law enforcement officials lure a
person into committing a crime. two-pronged test for entrapment defenses
the criminal design must have originated with law enforcement
the defendant must not be predisposed to commit the crime; some jurisdictions use different standards for determining predisposition
subjective standard, majority Rule – revolves around the answer to one question, “Was the defendant predisposed to commit the crime?”
objective standard, minority rule – focuses on the government’s inducement and asks the question, “Would an innocent person be induced to commit the crime by the officer’s acts?”
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Victim’s Consent In some circumstances, the accused can
claim that the victim gave consent for the act in question. Reasons why a victim’s consent will not be valid
the victim is a minor the victim has a mental disease or defect the victim is intoxicated to the point he/she is unable to
make a reasonable judgment consent is obtained by force or duress consent is obtained by fraudulent or deceptive means the victim has been judged to be legally incompetent the consent defense is precluded by the law in question
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Capacity Defenses May be used when the defendant
lacks the capacity or ability to control his or her actions or understand that the act was criminal in nature.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Infancy Defense Infancy defense – Although some states have sought to
modify the standard by statute, under the common law, children of tender age could not be held liable for criminal acts under the presumption that they lacked the capacity to tell right from wrong.
Under the common law standard: children under 7 years of age are conclusive presumed
incapable of knowing the wrongfulness of their crimes children 7-14 years of age have a rebuttable presumption
of incapacity. The burden of proof is on the prosecutor to prove beyond a reasonable doubt that the defendant appreciated the quality and nature of his/her actions.
children over 14 were treated as adults and presumed to fully appreciate the difference between right and wrong.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Intoxication Defense involuntary intoxication – occurring when a
person unknowingly ingests an intoxicating substance; most successful for the intoxication defense
persons who are involuntarily intoxicated are treated the same as insane defendants
voluntary intoxication – occurring when a person become willingly intoxicated; never used as a defense for crimes of general intent
cannot be used as an excuse or justification of a crime of homicide, to crimes involving negligence, recklessness, or strict liability
has been used as a defense to specific intent crimes where the intoxication prevents the Defendant from formulating the requisite intent
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Insanity Defense A defendant using the insanity
defense is claiming he/she lacked the mental state to understand the nature and consequences of the crime. If the defendant is successful, he/she would be committed to a mental hospital rather than prison. The defendant would remain there until the state determined the person to be sane.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
M’Naghten Rule The burden of proof for the insanity
defense is that “Every man is presumed to be sane and to possess a sufficient degree of reason to be responsible for his crimes, until the contrary be proved to (the jury’s) satisfaction; and that to establish a defense on the ground of insanity, it must be clearly proved.”
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Insanity Defense In 1886, Alabama adopted the more liberal “irresistible
impulse” test. In effect, this created a “temporary insanity” for people who committed “crimes of passion.”
Durham Test – only requires a “substantial lack of capacity; part of the Model Penal Code, but has not been adopted by all states.
guilty, but mentally ill – under special laws enacted in some states, defendants who do not meet the M’Naghten standard of a complete lack of capacity, but fall under the substantial lack of capacity standard are convicted and sent to a mental hospital; if they recover, they are sent to prison for the rest of their term.
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Capacity to Stand Trial definition– Common law has long held that a
person must be able to understand the proceedings against him and be able to interact with his attorneys in order have a fair trial.
If a defendant claims lack of capacity, the state must:
try the defendant, if he or she is competent to stand trial,
dismiss the charges, or commence civil proceedings to have the
defendant committed to a mental institution
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Competency Standard The standard for competency in many
jurisdictions comes from Justice Thurgood Marshall’s dissent in White v. Estelle, where he stated: “This Court has approved a test of incompetence which seeks to determine whether the defendant ‘has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding–and whether he has a rational as well as factual understanding of the proceedings against him.’ Dusky v. United States, 362 U. S. 402 (1960).”
Davenport: Basic Criminal Law, 2nd ed. © 2009 Pearson Education, Upper Saddle River, NJ 07458.All rights reserved
Incapacity and Punishment In cases where the death penalty has
already been imposed, convicts can postpone execution by claiming insanity just prior to execution.
In other cases, involving the imposition of time in prison, should insanity during incarceration occur, prisoners are moved to a psychiatric hospital for the remainder of their term. Should they still be insane at the end of their term, they may be committed to a mental hospital until they recover