Electronic copy available at: https://ssrn.com/abstract=3209587

INITIAL REACTIONS TO

CARPENTER V. UNITED STATES

Orin S. Kerr*

ABSTRACT

On June 22, 2018, the United States Supreme Court handed

down its much-anticipated Fourth Amendment ruling in Carpenter

v. United States. In the wake of Carpenter, Professor Kerr authored

three extensive blog posts on the decision that appeared at both

Lawfare and The Volokh Conspiracy. This paper presents the three

posts together in the order that they appeared. The first post

explores the basic reasoning of the opinion, the second post

discusses Carpenter’s impact on the law of subpoenas, and the third

post considers the timing of Carpenter searches.

TABLE OF CONTENTS

I. First Thoughts on Carpenter v. United States 1

(June 22, 2018)

II. Does Carpenter Revolutionize the Law of Subpoenas? 6

(June 26, 2018)

III. When Does a Carpenter Search Start 14

– and When Does It Stop?

(July 6, 2018)

* Frances R. and John J. Duggan Distinguished Professor of Law, University of Southern California Gould

School of Law.

Electronic copy available at: https://ssrn.com/abstract=3209587

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I. FIRST THOUGHTS ON CARPENTER V. UNITED STATES June 22, 20181

The Supreme Court has handed down its long-awaited decision in Carpenter v. United States. The

opinion is only an hour old as I start to write this, but I wanted to offer some initial thoughts that I

will also cross-post at Lawfare.

I’ll do it in the form of a Question and Answer, asking questions you may have and offering

answers as best I can. Also, rather than wait to the end and post all of my thoughts at once, I’m

going to post over time. I’ll start with a few basic questions and add more over the course of the

afternoon.

(1) What Did the Court Rule?

The Court ruled that access to a person’s historical cell site records -- or at least 7 days or more of

cell site records -- is a Fourth Amendment search because it violates the person’s “legitimate

expectation of privacy in the record of his physical movements.” The Court also held that accessing

those records requires a warrant.

(2) Who Wrote the Opinion, and What Was the Vote Breakdown?

The Chief Justice wrote the opinion. It was a 5-4 decision, with the Chief joined by the four liberal-

leaning Justices (Ginsburg, Breyer, Kagan, and Sotomayor). The four remaining Justices dissented

(Kennedy, Thomas, Alito, and Gorsuch). Each of the four dissenters wrote their own dissents,

which may explain why the opinion took so much time.

(3) Is There a Clear Majority Opinion, or Were There a Bunch of Concurrences?

There’s a clear majority. The case was 5-4, but none of the Justices who joined the majority wrote

separately and all joined the opinion in full. The only separate opinions were dissents.

(4) Okay, So What Was the Reasoning of the Majority Opinion?

Relying on the concurring opinions in United States v. Jones, the Court holds that a person has

“reasonable expectation of privacy in the whole of their physical movements.” Access to historical

cell site records violates that reasonable expectation of privacy because it is a “sweeping mode[e]

of surveillance” that gives the government the power of “near perfect surveillance, as if it had

attached an ankle monitor to the phone’s user.” It is “tireless and absolute surveillance.” The

surveillance is “detailed, encyclopedic, and effortlessly compiled.” It “provides an all-

encompassing record of the holder’s whereabouts.” As a result, it violates the reasonable

expectation of privacy people have in their physical movements from the Jones concurrences.

1 This post appeared at the Volokh Conspiracy at https://reason.com/volokh/2018/06/22/first-thoughts-on-carpenter-

v-united-sta. It appeared at Lawfare under a different title at https://www.lawfareblog.com/understanding-supreme-

courts-carpenter-decision

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2

(5) How Is Accessing Historical Cell-Site Records “Absolute Surveillance”? It’s Not Precise,

and It’s Only Generated When A Call is Made, Right?

This is one of the most interesting aspects of the opinion. Instead of focusing on the facts of this

case, the Court seems more interested in where the technology is thought to be going. The record

in this case indicates that the records only where precise to a range of 0.5 to 2 miles, and that

records where only generated when a call was actually placed. It just reveals the neighborhood the

phone was in when a call was made. But the Chief Justice’s opinion presents the technology as

vastly more invasive and detailed than the record indicates. It is absolute perfect surveillance, in

the Court’s vision, like a GPS device around a person’s ankle

In response to the dissent’s pointing out the record, the Chief Justice says we have to take into

account where the technology is going. “The accuracy of CSLI is rapidly approaching GPS-level

precision,” the Chief Justice predicts, and the Court has to adopt a rule in light of what the

technology will look like then. In effect, the technology isn’t actually perfect and absolute

surveillance now, but the Justices are confident that it is going to be that eventually.

(6) Does Any Accessing Historical Cell-Site Records Count as A Search? Or Is Short-Term

Warrantless Surveillance Permitted?

We don’t know. Regular readers will recall the debate over the mosaic theory, by which perhaps

short-term surveillance is not a search but long term surveillance is, on the thinking that long-term

surveillance lets the governent create a mosaic of a person’s life. That was key to

the Jones concurrences. The Court leaves open that there may be mosaic-based short-term vs.

long-term distinctions for cell-site collection: “[W]e need not decide whether there is a limited

period for which the Government may obtain an individual’s historical CSLI free from Fourth

Amendment scrutiny, and if so, how long that period might be. It is sufficient for our purposes

today to hold that accessing seven days of CSLI constitutes a Fourth Amendment search.”

(7) Might This Reasoning Be Based on Equilibrium-Adjustment?

Indeed! I have written about how the Supreme Court often engages in equilibrium-

adjustment when new technology threatens the balance of government power. If technology gives

the government too much new power that can be abused based on old rules, the Court expands

legal protection to restore old levels of power and limit abuses. On the flip side, if technology

threatens to narrow government power too much that can unduly limit the government’s ability to

solve crimes under old rules, the Court shrinks legal protection to restore old levels of power and

ensure the government can still solve enough cases.

In Carpenter, the Chief Justice is very clear that this what is going on. Throughout the opinion, he

roots his analysis in the idea that cell-site surveillance is a new tool that gives the government new

power that can be abused, and that the law must change course to ensure that the government

doesn’t get too much power from a mechanical application of the old rules.

Here’s The Chief Justice in the conclusion:

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As Justice Brandeis explained in his famous dissent, the Court is obligated—as

“[s]ubtler and more far-reaching means of invading privacy have become available

to the Government”—to ensure that the “progress of science” does not erode Fourth

Amendment protections. Olmstead v. United States, 277 U. S. 438, 473–474

(1928). Here the progress of science has afforded law enforcement a powerful new

tool to carry out its important responsibilities. At the same time, this tool risks

Government encroachment of the sort the Framers, “after consulting the lessons of

history,” drafted the Fourth Amendment to prevent. Di Re, 332 U. S., at 595

There’s another revealing passage when the Chief Justice is responding to Justice Alito on what

the standard should be for accessing the records, assuming that it is a search. After going through

some legal analysis, the Chief Justice sort of stops and says (without using the label), but this is

equilibrium-adjustment! Here’s the paragraph:

JUSTICE ALITO overlooks the critical issue. At some point, the dissent should

recognize that CSLI is an entirely different species of business record—something

that implicates basic Fourth Amendment concerns about arbitrary government

power much more directly than corporate tax or payroll ledgers. When confronting

new concerns wrought by digital technology, this Court has been careful not to

uncritically extend existing precedents. See Riley, 573 U. S., at ___ (slip op., at 10)

(“A search of the information on a cell phone bears little resemblance to the type

of brief physical search considered [in prior precedents].”)

The new technology is a “new phenomenon,” and an “entirely different species” of record. Old

rules don’t apply. Instead, the Court goes back to “the critical issue” of “basic Fourth Amendment

concerns about arbitrary government power” that are “wrought by digital techology.” In other

words, equilbrium-adjustment.

(8) Does This Reasoning Apply Just For Physical Location Tracking, Or Does It Apply More

Broadly?

That’s the big question. On one hand, the reasoning of the opinion is largely about tracking a

person’s physical location. The opinion takes as a given that you have a reasonable expectation of

privacy in the “whole” of your “physical movements.” The Court has never held that, so it’s sort

of an unusual thing to just assume! But the Court seems to be getting it mostly from Justice

Alito’s Jones concurrence, and the idea, as Alito wrote in Jones, that “society’s expectation has

been that law enforcement agents and others would not— and indeed, in the main, simply could

not—secretly monitor and catalogue every single movement of an individual’s car for a very long

period.”

The opinion is mostly rooted in that idea of tracking physical location, and in particular the idea

of near perfect and total surveillance that allows the government to monitor us as if we had GPS

trackers stapped to our ankles. Near the end, the Chief Justice adds a very interesting paragraph

saying that the opinion is narrow. It’s worth reading:

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Our decision today is a narrow one. We do not express a view on matters not before

us: real-time CSLI or “tower dumps” (a download of information on all the devices

that connected to a particular cell site during a particular interval). We do not

disturb the application of Smith and Miller or call into question conventional

surveillance techniques and tools, such as security cameras. Nor do we address

other business records that might incidentally reveal location information. Further,

our opinion does not consider other collection techniques involving foreign affairs

or national security. As Justice Frankfurter noted when considering new

innovations in airplanes and radios, the Court must tread carefully in such cases, to

ensure that we do not “embarrass the future.” Northwest Airlines, Inc. v. Minnesota,

322 U. S. 292, 300 (1944).

(As an aside, isn’t it interesting that collection of cell-site records is a new-fangled surveillance

methid but security cameras are merely “conventional techniques and tools”? Why is that? Because

people can see cameras but not cell sites? But I digress.) In a footnote, he adds in response to a

dissent that “we “do not begin to claim all the answers today, and therefore decide no more than

the case before us.” Perhaps even more significantly, the Chief elsewhere says that it will be “the

rare case where the suspect has a legitimate privacy interest in records held by a third party,” and

that in “the overwhelming majority of investigations” there will be no Fourth Amendment

protection.

So you could look at that language and say that this is a narrow opinion only about perfect location

tracking by Big Brother.

On the other hand, there’s lots of language in the opinion that cuts the other way. Although the

Court “decides no more than the case before us,” it also recasts a lot of doctrine in ways that could

be used to argue for lots of other changes. Its use of equilibrium-adjustment will open the door to

lots of new arguments about other records that are also protected. For example, what is the scope

of this reasonable expectation of privacy in the “whole” of physical movements? Why is there?

The Jones concurrences were really light on that, and Carpenter doesn’t do much beyond citing

them for it: What is this doctrine and where did it come from? (And what other reasonable

expectations of privacy in things do people have that we didn’t know about, and what will violate

them?)

In addition, Carpenter’s view of Miller and Smith is narrower than the opinions

in Miller and Smith suggest. Carpenter suggests that the third-party doctrine is less of the bright-

line rule that the cases suggest and more of a fact-specific standard. At the very least that is going

to invite a boatload of litigation on how far this new reasoning goes.

(9) What’s the Status Of the Third-Party Doctrine?

It lives, but there is an equilibrium-adjustment cap on it. The old understanding was that the third-

party doctrine is a bright-line rule: When you voluntarily disclose information to someone, whether

to an undercover officer or a business you’re working with, you don’t have Fourth Amendment

rights in the recipient’s copy of that information. Chief Justice Roberts says that the third-party

doctrine is more limited than that.

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As I read him, the Chief seems to be saying that there is an equilibrium-adjustment limit on the

third-party doctrine. Once the third-party doctrine starts to give the government massive new

powers, the third-party doctrine may no longer apply. Here’s the key passage:

There is a world of difference between the limited types of personal information

addressed in Smith and Miller and the exhaustive chronicle of location information

casually collected by wireless carriers today.The Government thus is not asking for

a straightforward application of the third-party doctrine, but instead a significant

extension of it to a distinct category of information.

Part of the thinking here is an adoption of Carpenter’s rhetoric in his brief that the third-party

doctrine only “diminishes” an expectation of privacy. That’s not what the cases say; the cases say

that the doctrine entirely eliminates an expectation of privacy. But by adopting the idea that the

third-party doctrine only “diminishes” an expectation of privacy, the Court effectively sets up a

hierarchy: Because the information revealed by cell-site records collection is claimed to be vastly

more revealing and sensitive than the records in Smith and Miller, and the surveillance is more

pervasive, the third-party doctrine’s diminishing of privacy still leaves a lot of privacy behind that

is enough to satisfy the Fourth Amendment.

In effect, disclosure is enough to eliminate privacy when the records disclosed only involve a

normal amount of privacy. But when the records are super private and pervasive, disclosure isn’t

enough to eliminate Fourth Amendment rights.

In his dissent, Justice Gorsuch suggests that this means that Smith and Miller are “on life support,”

but I don’t see that in the majority. After all, the Chief says in his opinion that [w]e do not disturb

the application of Smith and Miller.” Rather, the idea seems to be that there’s an equilibrium-

adjustment limit on how far the Justices will take the third-party doctrine. At some point the

surveillance is just too much to allow, and at that point the third-party doctrine doesn’t apply. The

facts of Smith and Miller were on one side of the line, and seven days of this technology crossed

over to the other side.

What other technology and its uses might also cross it? We don’t yet know.

Electronic copy available at: https://ssrn.com/abstract=3209587

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II. DOES CARPENTER REVOLUTIONIZE THE LAW OF SUBPOENAS? June 26, 20182

The Supreme Court’s decision in Carpenter v. United States has lots of new directions in it. One

direction that some commentators have focused on is its impact on the law of subpoenas. For

example, Marty Lederman writes today that the subpoena analysis in Carpenter is “extraordinary”

and “groundbreaking” and may trigger “a fundamental transformation of national subpoena

practices.” In their dissents, Justice Alito and Justice Kennedy also suggest that the subpoena

analysis in the case is a major break from the past.

I have a different view. There is a lot that is extraordinary and groundbreaking in Carpenter. But

I think Carpenter makes only a small and likely necessary resolution of an unsettled question in

the law of subpoenas. In this post, I will explain the problem and say why I think Carpenter doesn’t

have a major impact on subpoena law. I will also argue that if you think the majority is right on

the law of searches, it is also likely right, at least as to the result, in its subpoena holding.

This is a really long post, so here’s a roadmap of where I’m going.

Part I introduces the two basic kinds of legal process in the law of criminal procedure: warrants

and subpoenas. Part II explains how the dynamic of third-party storage alters the balance of

criminal procedure law on which the two kinds of legal process are based. Part III shows that

when a target has constitutional rights in remotely-stored information, there was a legal uncertainty

before Carpenter on whether the subpoena rules continue to apply – but a good reason, rooted in

a need to maintain the balance of the Fourth Amendment, to think they don’t.

Part IV turns to Carpenter and shows how the majority’s decision responds to the problems

explained in Parts I-III. Finally, Part V argues that the majority’s approach to the law of subpoenas

is only a small and likely necessary resolution of how the subpoena doctrine applies that should

have relatively limited impact on the law of criminal procedure.

I. The Two Paths of Legal Process

Imagine the government believes that a person possesses evidence of crime in his home.

Investigators want to get that evidence. But how? The law traditionally provides two forms of

legal process to do it.

The first path, and the most familiar, is to get a warrant. A warrant authorizes the investigators to

physically break into the place where the evidence is thought to be, rifle through the place, and

take away the evidence they find.

A warrant is the best known form of government legal process in criminal investigations. But it’s

not the only one. The government can also obtain evidence using a grand jury subpoena. A grand

2 This post appeared at the Volokh Conspiracy at https://reason.com/volokh/2018/06/26/does-carpenter-

revolutionize-the-law-of. It appeared at Lawfare at https://www.lawfareblog.com/does-carpenter-revolutionize-law-

subpoenas.

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jury subpoena directs its recipient to bring the described evidence to the grand jury at some future

place and time. Unlike a warrant, the police don’t barge in and take stuff. Rather, the subpoena

recipient is tasked with gathering the evidence himself, from the stuff in his possession, and later

bringing the evidence to the grand jury (or the police/prosecutors working with the grand jury).

Recognizing these two path matters because they are regulated by two very different legal regimes.

When the government gets a search warrant, the Fourth Amendment is the big limit on the police.

The police need to show probable cause to believe that the evidence will be located in the place to

be searched. They need to specifically describe the place to be searched, and they need to describe

specifically the evidence that they are seeking.

The law of grand jury subpoenas for evidence is very different. The Fourth Amendment applies,

but its role is modest. No probable cause is required to issue a subpoena. The government can

issue a subpoena – in the name of the grand jury, but really by the prosecutors who run the grand

jury – just to see if a crime might have been committed. A recipient does have Fourth Amendment

rights at stake, but he can challenge the subpoena only on the ground that it is overbroad or

compliance is overly burdensome.

The flip side is that the recipient of a subpoena can challenge it under the Fifth Amendment right

against self-incrimination. The recipient can claim that complying with the subpoena implies

certain statements – that the records exist, that the recipient has them, and that the recipient thinks

that they are authentic – and that he can’t be forced to testify against himself.

Note the key difference. When investigators want to break in and get the evidence themselves,

they proceed by way of a warrant and the Fourth Amendment is the big legal barrier. When

investigators want to have the evidence produced for them, they proceed by way of a subpoena

and the Fifth Amendment is the big legal barrier. Two different paths with two different legal

regimes limiting government access.

II. What Changes When A Target’s Evidence Is Stored With A Third Party?

Now let’s complicate matters. Let’s imagine that a target of an investigation has stored his

evidence with someone else. Maybe Alice leaves a box of her personal files with Bob to store in

Bob’s basement. Maybe Carl becomes a customer at a mailbox service that receives and stores

his mail for him. Maybe David keeps his files stored in “the Cloud” with an online cloud service

like Dropbox. In each of these cases, the person’s evidence is located far from them in the

possession of another person or company.

Now imagine you’re the government, and you want to collect the suspect’s evidence. That

evidence is now stored with a third party, whether it’s Bob, the mailbox service, or Dropbox. The

question is, how does the fact of third-party possession change the legal framework? What law

applies to collecting the evidence now?

The option to get a warrant and conduct the search directly remains. You could break in and take

the evidence. That would be legal, but it’s probably a bit unseemly. For example, you probably

don’t want local police breaking into Dropbox’s company headquarters and looking through its

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servers on their own to find a user’s files. And that wouldn’t be necessary, either, because the

companies are just neutral parties. The police can work with them to retrieve the evidence. So

even if a warrant is obtained, the police would want the third-party providers to gather the

information. In effect, it would be a warrant that is executed like a subpoena.

But that brings us to the key question. Can the government still use a subpoena to get the

information stored with third parties? Can they serve a subpoena on Bob for Alice’s box of files?

Can they serve a subpoena on the mailbox service for Carl’s mail? Can they serve a subpoena on

Dropbox for David’s files?

If you assume that none of the targets have Fourth Amendment rights in the records that they have

stored with third parties, then the answer is easy. Not only can the government use a subpoena,

but there is very little in the way of limits on that power. By hypothesis, the targets have no Fourth

Amendment rights. And unlike with the subpoena stored by the target, there is no Fifth

Amendment privilege to assert. This is a big difference. The Supreme Court held in Fisher v.

United States that the recipients of a subpoena can’t assert the Fifth Amendment privilege of

someone else. In addition, companies have no Fifth Amendment privilege to assert.

This means that if you assume no Fourth Amendment rights for the targets, the fact of third-party

storage greatly shifts the legal terrain: It empowers the government by eliminating Fifth

Amendment protection when the government wants to proceed by subpoena. The only

constitutional limit now is that the possessors of the evidence can try to assert their modest Fourth

Amendment objections based on the burdensomeness of complying with the subpoena. But in most

cases that’s a very limited objection. And because the Internet and communications networks

work using third parties, the shift to third-party storage is a really big deal.

Statutes can certainly come in and try to even the playing field. That’s exactly what the Stored

Communications Act was designed to do. It imposes a court order requirement using the

“reasonable suspicion” standard on access to unprotected records even though the Fourth

Amendment doesn’t apply. But that’s a statute, not the Constitution.

III. The Puzzle of Fourth Amendment Rights in Records Stored With a Third Party

Now we get to the big question: How does the subpoena power apply if we assume that the target

retains Fourth Amendment rights in the records stored with the third party? Imagine Alice has

Fourth Amendment rights in the contents of the box she left with Bob. Imagine Carl has Fourth

Amendment rights in the mail left with the mailbox service. And imagine David has Fourth

Amendment rights in the files stored with Dropbox. Can the government subpoena those records

from the possessor (Bob/mailbox/Dropbox) just like it could if the target had no Fourth

Amendment protection in the records?

Appreciate the importance of the question. If the traditional subpoena rules continue to apply, then

the fact of the target having Fourth Amendment rights in the information doesn’t matter all that

much. The government can still just subpoena all the protected records, and they can do so without

probable cause or even reasonable suspicion. The only apparent impact of finding the target has

Fourth Amendment rights would be that the target has standing to challenge the subpoena. But

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because the only Fourth Amendment limit on the subpoena is the burdensomeness on the recipient

of the subpoena, it’s not clear that the this would matter.

If the traditional subpoena rules continue to apply, then, we end up with a equilirbrium-adjustment

problem: Applying the old law to the new facts of third-party storage may suddenly give the

government a major power advantage by eliminating Fifth Amendment privilege from the

subpoena equation. Technological change could put the government in a position where they could

subpoena everything, with few limits, even if the target of the investigation has Fourth Amendment

rights in the information.

Until Friday’s Carpenter decision, there was surprisingly little caselaw on what legal standard

governed use of a subpoena on a third-party to collect information in which a target has Fourth

Amendment rights. And believe me I have looked, as I’ve been interested in this issue for a long

time. (I wrote an amicus brief partially on this question in 2002, and I had a section about it in the

2006 First Edition of my Computer Crime Law casebook.) The main reason for the absence of

cases is the third-party doctrine. Under the third-party doctrine, targets usually don’t have any

Fourth Amendment rights in the records the government might want to subpoena from the third

party.

The sparse caselaw that does exist has tended to involve subpoenas to compel the possessor to

hand over sealed documents when the government then obtained a warrant to open them. See,

e.g., United States v. Barr, 605 F. Supp. 114, 119 (S.D.N.Y. 1985) (mail box service). But that

doesn’t answer the question of whether a subpoena could be used to open the documents.

In other cases, courts simply said without any analysis that target Fourth Amendment rights meant

that a warrant was required. See, e.g., United States v. Warshak, 631 F.3d 266, 288 (6th Cir. 2010)

(holding that a user has Fourth Amendment rights in the contents of their remotely stored e-mail

and therefore a warrant is required); United States v. Bach, 310 F.3d 1063, 1066 n.1 (8th Cir. 2002)

(noting, in a case involving access to remotely stored e-mail, that the court “analyze[s] this case

under the search warrant standard, not under the subpoena standard”)

Given all of this, the issue of whether a subpoena could be used to access target-protected data

held by a third party was uncertain. For what it’s worth, my own view has been that if you

recognize a target’s full Fourth Amendment rights in the records, then the subpoena standard is

insufficient. As I wrote in a 2010 article (at page 1044), the reason is that a subpoena can compel

a provider to hand over records but it can’t be used to open the constitutionally-protected set of

records obtained. The government could in theory subpoena the records under my view, but it

would still need a warrant to open them. A warrant is still required.

But that was just my view, and until Carpenter there was no Supreme Court discussion of the

question.

IV. The Subpoena Analysis in Carpenter

That brings us – finally! – to Carpenter. Up through page 18 of the Court’s opinion, the majority

concludes that a cell phone user has Fourth Amendment rights in the cell phone provider’s cell site

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location records. The next question is what standard the government must satisfy to compel access

to those records. The Chief Justice rather breezily concludes that a warrant is required, finding

that the statutory Terry standard of the Stored Communications Act is insufficient.

The Chief Justice then turns to contrary arguments in Justice Alito’s dissent. In his dissent, Justice

Alito notes that the traditional standard for compelling disclosure is the mere reasonableness

subpoena standard. Because the statutory Terry standard is pretty much a subpoena with a required

finding of reasonable suspicion, Justice Alito argues that the same constitutional analysis should

apply to that court order as traditionally applies to subpoenas.

The Chief Justice disagrees with the following passage. This is the language that some think is a

radical change, so it’s worth reprinting in full:

JUSTICE ALITO contends that the warrant requirement simply does not apply

when the Government acquires records using compulsory process. Unlike an actual

search, he says, subpoenas for documents do not involve the direct taking of

evidence; they are at most a “constructive search” conducted by the target of the

subpoena. Post, at 12. Given this lesser intrusion on personal privacy, JUSTICE

ALITO argues that the compulsory production of records is not held to the same

probable cause standard. In his view, this Court’s precedents set forth a categorical

rule—separate and distinct from the third-party doctrine—subjecting subpoenas to

lenient scrutiny without regard to the suspect’s expectation of privacy in the

records. Post, at 8–19.

But this Court has never held that the Government may subpoena third parties for

records in which the suspect has a reasonable expectation of privacy. Almost all of

the examples JUSTICE ALITO cites, see post, at 14–15, contemplated requests for

evidence implicating diminished privacy interests or for a corporation’s own books.

The lone exception, of course, is Miller, where the Court’s analysis of the third-

party subpoena merged with the application of the third-party doctrine. 425 U. S.,

at 444 (concluding that Miller lacked the necessary privacy interest to contest the

issuance of a subpoena to his bank).

JUSTICE ALITO overlooks the critical issue. At some point, the dissent should

recognize that CSLI is an entirely different species of business record—something

that implicates basic Fourth Amendment concerns about arbitrary government

power much more directly than corporate tax or payroll ledgers. When confronting

new concerns wrought by digital technology, this Court has been careful not to

uncritically extend existing precedents. See Riley, 573 U. S., at ___ (slip op., at 10)

(“A search of the information on a cell phone bears little resemblance to the type

of brief physical search considered [in prior precedents].”).

If the choice to proceed by subpoena provided a categorical limitation on Fourth

Amendment protection, no type of record would ever be protected by the warrant

requirement. Under JUSTICE ALITO’s view, private letters, digital contents of a

cell phone—any personal information reduced to document form, in fact—may be

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collected by subpoena for no reason other than “official curiosity.” United States v.

Morton Salt Co., 338 U. S. 632, 652 (1950). JUSTICE KENNEDY declines to

adopt the radical implications of this theory, leaving open the question whether the

warrant requirement applies “when the Government obtains the modern-day

equivalents of an individual’s own ‘papers’ or ‘effects,’ even when those papers or

effects are held by a third party.” Post, at 13 (citing United States v. Warshak, 631

F. 3d 266, 283–288 (CA6 2010)). That would be a sensible exception, because it

would prevent the subpoena doctrine from overcoming any reasonable expectation

of privacy. If the third-party doctrine does not apply to the “modern-day equivalents

of an individual’s own ‘papers’ or ‘effects,’” then the clear implication is that the

documents should receive full Fourth Amendment protection. We simply think that

such protection should extend as well to a detailed log of a person’s movements

over several years.

This is certainly not to say that all orders compelling the production of documents

will require a showing of probable cause. The Government will be able to use

subpoenas to acquire records in the overwhelming majority of investigations. We

hold only that a warrant is required in the rare case where the suspect has a

legitimate privacy interest in records held by a third party.

In his dissent, Justice Alito responds:

[The majority] decides that a “search” of Carpenter occurred within the meaning of

the Fourth Amendment, but then it leaps straight to imposing requirements that—

until this point— have governed only actual searches and seizures. See ante, at 18–

19. Lost in its race to the finish is any real recognition of the century’s worth of

precedent it jeopardizes. For the majority, this case is apparently no different from

one in which Government agents raided Carpenter’s home and removed records

associated with his cell phone.

Against centuries of precedent and practice, all that the Court can muster is the

observation that “this Court has never held that the Government may subpoena third

parties for records in which the suspect has a reasonable expectation of privacy.”

Ante, at 19. Frankly, I cannot imagine a concession more damning to the Court’s

argument than that. As the Court well knows, the reason that we have never seen

such a case is because—until today— defendants categorically had no “reasonable

expectation of privacy” and no property interest in records belonging to third

parties. See Part II, infra. By implying otherwise, the Court tries the nice trick of

seeking shelter under the cover of precedents that it simultaneously perforates.

Not only that, but even if the Fourth Amendment permitted someone to object to

the subpoena of a third party’s records, the Court cannot explain why that individual

should be entitled to greater Fourth Amendment protection than the party actually

being subpoenaed. When parties are subpoenaed to turn over their records, after all,

they will at most receive the protection afforded by [the subpoena cases] even

though they will own and have a reasonable expectation of privacy in the records

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at issue. Under the Court’s decision, however, the Fourth Amendment will extend

greater protections to someone else who is not being subpoenaed and does not own

the records. That outcome makes no sense, and the Court does not even attempt to

defend it.

V. What’s Happening Here, and a (Partial) Defense of the Majority’s Approach

What’s going on here? Although the majority could articulate the point a lot better than it did, I

take it what the Court is doing is engaging in equilibrium-adjustment – one operating over the

combination of the Fourth and Fifth Amendment together.

In a world of local storage, where suspects keep their evidence in their possession, the government

has the two paths explained in Part I. They are limited by Fourth Amendment probable cause if

they want to break in themselves, and they are limited by the Fifth Amendment right against self-

incrimination if they want to compel records. But computers and the Internet are new worlds of

remote storage. A typical Internet user has his protected records stored hundreds or thousands of

miles away in the possession of big companies that have no Fifth Amendment rights and can’t

assert them for their users. Applying the usual subpoena standard when the target has Fourth

Amendment rights would result in a dramatic expansion of government power that would let the

government get everything with few limits.

By insisting on a warrant requirement, the Court is restoring the prior equilibrium. Changing the

legal rule when a third-party has Fourth Amendment rights in the information corrects for the

otherwise distorting effect of third-party storage on the degree of legal protection. The same

warrant rule applies that would apply if this were a traditional case of local storage. In effect, the

Court’s approach collapses the two paths into one when there is third-party storage, which can

account that the factual assumptions on which the legal framework for subpoenas has been

generated– an environment in which targets are protected from subpoenas by the Fifth Amendment

– no longer apply.

To be clear, I don’t think the Justices were thinking about the shift from the Fifth Amendment

protection to the Fourth Amendment protection. I suspect they were just thinking about this as a

Fourth Amendment. But the Chief Justice’s opinion recognizes that you need to have a full warrant

protection for the third-party stored information or else the target’s newfound rights don’t mean

much. As the Chief Justice states, “If the choice to proceed by subpoena provided a categorical

limitation on Fourth Amendment protection, no type of record would ever be protected by the

warrant requirement.”

All of this suggests that the operative legal rule here is that the existence of third-party rights

triggers a higher protection for the third party to restore the equilibrium. As the Court holds, “a

warrant is required in the rare case where the suspect has a legitimate privacy interest in records

held by a third party.” If the government wants to get records that a suspect has stored, without

the help of the suspect, the same warrant protection applies regardless of whether the suspect has

stored the information at home or remotely.

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This understanding illuminates important limits on the Court’s subpoena rule and shows why it

will only apply “in the rare case.” For example, I gather that rule wouldn’t stop the government

from issuing a subpoena to the target for the target’s records that he has stored in the Cloud, for

example. The fact that the records are “held by a third party” doesn’t matter because the

government isn’t getting the records from the third party but rather is going directly to the suspect.

The Fifth Amendment issues would then control, leaving the two paths as they were without third-

party storage.

Similarly, this approach shows why I disagree with this interpretation of Carpenter by Marty

Lederman in his post today:

At a minimum, however, it is fair to assume that questions of the reasonable

expectations of privacy of the “first party” subject of the records sought by

production orders will now play a much larger role in subpoena litigation and other

challenges to compulsory process.

I don’t think that’s right. Or at least I don’t think it shouldn’t be right. As I see it, the first party

subject to the subpoena has all the protections it has always had: Mostly Fifth Amendment

protections against complying with any subpoena under the act of production doctrine. That’s the

traditional two paths described in part one, and I don’t think it changes in a case of local possession.

Carpenter’s subpoena holding reflected a need for equilibrium-adjustment; it shouldn’t change

anything in traditional cases where no equilibrium-adjustment is needed

To be sure, there are some difficult questions of application of the majority’s rule. I explored these

issues a year ago in a long blog post, Third Party Rights and the Carpenter Cell-Site Case. For

example, who gets notice of the government’s access? Who can object? As I wrote then:

Is the idea that a company served with a subpoena for business records has to figure

out if the subpoena implicates only its own Fourth Amendment rights (in which

case the subpoena complies with the Fourth Amendment so long as it is not

overbroad) or if it also implicates a user’s Fourth Amendment rights (in which case

the subpoena is insufficient and a warrant is required?). If the government issues a

subpoena for business records and it turns out that a customer also had rights in the

data, would we say that compelled compliance with the subpoena violated the rights

of the user but not the company?

These are issues to work through, I recognize, but I gather they should apply only in “the rare case”

when a third-party has stored records with a target’s protected information.

All of this is not to suggest that I think the majority’s subpoena holding has it quite right. I would

have probably preferred the Court take the view I suggested in my 2010 article noted above, by

which the government can still technically subpoena the records but can’t open the records without

a warrant. This avoids the conceptual puzzles that Justice Alito notes by having the same rule

apply in all situations: A subpoena can be used to compel records without probable cause, but the

government needs a warrant to open Fourth Amendment protected records. That approach isn’t

perfect, for reasons I explore in my article (see footnote 170). But I think it would be better.

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Finally, I am certainly sympathetic with the concerns of Justice Alito and Justice Kennedy in their

dissents. I think Carpenter’s search holding is wrong. In my view, users don’t have Fourth

Amendment rights in their historical cell-site records. But if you accept that erroneous holding as

correct, and you then need to figure out what the reasonableness standard is for compelling access,

I think something like the majority’s rule, in which the target is still ultimately protected by the

same protections that would apply if the information were locally stored, is probably right.

Carpenter creates a strange new world in a lot of ways. But I see its subpoena holding as more a

necessary corollary to its search holding and not a groundbreaking departure in its own right.

III. WHEN DOES A CARPENTER SEARCH START

– AND WHEN DOES IT STOP? July 6, 20183

The Supreme Court’s recent decision in Carpenter v. United States raises lots of fascinating and

novel Fourth Amendment questions. In this post I want to focus on one important set of questions:

When does a Carpenter search start, and when does it stop? I don’t have a lot of answers to these

question. But the questions are important to consider. This post will explore the questions and will

end with a set of hypotheticals to bring out the tough issues.

This is a long post, so here is a roadmap. I’ll begin by explaining why the timing of Fourth

Amendment searches was pretty easy before Carpenter, and I’ll turn next to why Carpenter

complicates the issue. I’ll then discuss the stages of surveillance and explain why the timing of

Carpenter searches is pretty important. After briefly covering the timing of searches suggested by

the Jones concurrences, the next section goes through the language of Carpenter and argues that

the opinion leaves the timing questions pretty open. I’ll end with four hypotheticals designed to

bring out different ways of thinking about when Carpenter searches start and stop.

I. Before Carpenter, the “When” of Search Law Was Simple

In traditional Fourth Amendment law, identifying when a search starts and stops is easy. That’s

true because Fourth Amendment law has always before been connected to a place or thing. There

was always some specific place, thing, or person that was searched, and the search occurred when

the information about that place or person was revealed. The place searched could be a house (as

in Kyllo), a structure (the phone booth in Katz), a car (as in the Jones majority), or a person (like

a Terry frisk). But it was always a specific and identifiable place, thing, or person – what the text

of the Fourth Amendment refers to as the “persons, houses, papers, and effects” that the

Amendment protects.

3 This post appeared at the Volokh Conspiracy at https://reason.com/volokh/2018/07/06/when-does-a-carpenter-

search-start-and-w. It appeared at Lawfare at https://www.lawfareblog.com/when-does-carpenter-search-start-and-

when-does-it-stop.

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Identifying when a search occurs under this traditional approach is very simple. You just look at

the moment when information from the place, thing, or person is revealed to the government.

Figuring out the timing of that search is traditionally straightforward. For example, imagine the

police break open a door to an apartment and rifle through its contents for an hour before leaving.

Identifying when the search occurred is obvious. The search begins when the door is opened, lasts

for an hour, and ends when the police leave. It’s pretty intuitive.

II. How Carpenter Makes the “When” Question Difficult

The timing of a Carpenter search does not seem intuitive, however. Carpenter is unique among

majority opinions of the Supreme Court in that it recognizes a right against the government

collecting a set of facts in the abstract. And that unique kind of right has big implications for the

timing of Carpenter searches.

Let me explain what I mean. The starting premise of the Carpenter opinion is that, at some point

in the past, you wouldn’t have expected the government to be able to collect lots of location

information about a suspect. “Prior to the digital age,” Carpenter states, “law enforcement might

have pursued a suspect for a brief stretch, but doing so for any extended period of time was difficult

and costly and therefore rarely undertaken.” Quoting Justice Alito’s Jones concurrence, Carpenter

concludes that this means that there was in the past a reasonable expectation “that law enforcement

agents and others would not—and indeed, in the main, simply could not—secretly monitor and

catalogue every single movement” of a person over time.”

Accessing CSLI is a search, Carpenter reasons, because that has changed. Because technology

has now made that kind of surveillance easy and potentially very common, the law needs to step

in and make that surveillance difficult and rare again. As I have written before, this is the theory

of equilibrium-adjustment. When technology dramatically expands the government’s power under

an old legal rule, the thinking goes, the Court changes the legal rule to restore the prior level of

government power. To ensure that the government doesn’t have unlimited power to catalog your

movements over time, Carpenter holds that a search occurred and a warrant was needed. New

technology means that you no longer have a reasonable expectation of privacy in your movements

over time; the law gives back to you the reasonable expectation of privacy that you once had. The

law giveth what technology taketh away.

But when exactly does the search occur? The Court’s phrasing on this point is fascinating. The

majority writes, in a key section, that “[t]he location information obtained from Carpenter’s

wireless carriers was the product of a search.” The product of a search. A search occurred at some

point, such that at the end we can say that a search caused the information to be obtained. But

exactly when?

I think this is hard to figure out because Carpenter holds, for the first time, that a search occurred

without it being a taking of information from any particular place, thing, or person. A search

occurred because it needed to have occurred to regulate a practice that needed to be regulated to

keep the government from having too much power. But the gathering of information was not

taken from a particular place or thing or person at a particular moment. Rather, the government

simply ended up with too much information about someone. How it ended up with too much

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information isn’t particularly relevant in the Court’s view. The point is the result, not the process.

Somewhere in the steps that ended up with the government getting all that information, a search

occurred.

III. The Stages of Surveillance

Why does this matter? It matters because modern systems of records collection and access often

have several different stages. It’s often important to figure out which stage or stages is the one

that counts as a Fourth Amendment search.

Let’s break down how it might work when the government ends up with cell site location records.

I will break down the process into eight stages, some of which will blend together in practice but

that may be conceptually helpful to keep distinct. To be clear, the eight stages are highly stylized

and somewhat arbitrary; this or different methods of surveillance can be described differently. But

at least as an exercise, consider the following eight steps.

(1) Creation of the Record. The relevant record first must be created, either because it is

necessarily created to deliver the product or services or because a computer was programmed to

create the record for other reasons. For example, if a cell phone call is made from an account at

2:34pm, and cell site 2342837413 is used to connect the call, the network will have generated that

information.

(2) Preservation of the Record. Next the record must be stored. Here the cellular provider

decides that this particular record will be saved and preserved, either for its own business purposes

or pursuant to a legal obligation.

(3) Creation of a Database. The cellular provider takes all of the similar records and puts them

into a database with similar records. For example, if a person made five phone calls on a particular

day, the provider might have a database file for that day that looks like this:

March 2 at 2:34pm connection to site 2342837413.

March 2 at 3:09pm connection to site 2342837413.

March 2 at 4:12pm connection to site 2342837413

March 2 at 4:18pm connection to site 1893472393.

March 2 at 4:51pm connection to site 2342837413.

(4) The Database File Is Sent to The Analyzing Agency. Acting pursuant to a court order, he

cellular provider takes the database file and sends it to the government. The file is received by the

government but not yet opened.

(5) The Database File Is Opened by The Analyzing Agency. The government agency opens

the file and a person there examines the data.

(6) Another Database Is Obtained to Make The First Database File Useful. In this case, the

initial file was a list of times and raw numbers of cell sites. The raw numbers don’t tell you much

yet, though, as you don’t yet know where the cell sites are. (All you know is that the phone was

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using one cell site, then used a second, then went back to the first.) To get locations from the

database you need a second file, one that associates cell site numbers with their physical locations.

In our case, the cellular provider might then send on a second file that looks like this:

Site 2342837413 is located at 6th Street and Elm Road.

Site 2362383929 is located at 23rd Street and Elm Road.

Site 1283839292 is located at 96th Street and Johnson Place.

Site 1893472393 is located at 47th Street and Baker Avenue.

(7) The Databases Are Combined. At this stage the two databases are put together to make the

information useful in a way that can be easily queried. In this case, putting the entries together

might look like this:

March 2 at 2:34pm connection to the site at 6th Street and Elm Road..

March 2 at 3:09pm connection to the site at 6th Street and Elm Road.

March 2 at 4:12pm connection to the site at 6th Street and Elm Road.

March 2 at 4:18pm connection to the site at 47th Street and Baker Avenue.

March 2 at 4:51pm connection to the site at 6th Street and Elm Road.

(8) The Combined Database Is Queried. With the database assembled, it can now be queried.

For example, a government analyst may query the database for the times that the phone was in the

area of Baker Avenue, with the response being March 2 at 4:18pm. Or the query might be for the

location of the phone after 4pm on March 2, which would return the three points at 4:12pm,

4:18pm, and 4:51 pm. Or the query might be for any times when the phone was in the area of 96th

Street and Johnson Place, which would return a null response.

Those are the eight stages. The big question: When does the search start, and when does it end?

IV. How the Jones Concurrences Answered the “When” Question

This problem first arose with the concurring opinions in United States v. Jones. In Jones, the

government placed a GPS device on a car the suspect was driving and monitored the car’s location

for 28 days. The Jones concurrences introduced the basic premise of Carpenter that a search

occurs because the monitoring simply gathered too much information. But the concurrences had

different ways to describe when the search occurred.

As I noted in The Mosaic Theory of the Fourth Amendment, the two concurring opinions in Jones

both looked beyond the initial data acquisition stage, albeit in somewhat different ways, for when

a search occurred:

Justice Alito’s opinion in Jones looked to whether a person reasonably expects others to

“secretly monitor and catalog” a person’s movements. Justice Sotomayor asked “whether

people reasonably expect that their movements will be recorded and aggregated” in a

manner that creates the mosaic. Cataloging and aggregating are verbs that describe

subsequent analysis instead of initial collection. These phrases suggest that the mosaic

theory requires some step beyond the acquisition stage.

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If so, courts will need to determine what kinds of post-acquisition conduct are required to

create a mosaic. Imagine the government collects a great deal of information but never

combines it into a single database. Has a mosaic been created? Or imagine the evidence is

collected into a database but never analyzed. Does that cross the line? If some analysis of

the evidence is required to trigger the mosaic, what kind of analysis counts? Does any

analysis suffice, or is there some threshold of sophistication or computational complexity

before the mosaic line has been crossed?

Carpenter seems to have adopted the basic mosaic approach of the Jones concurrences. Given

that the Jones concurrences suggest that some later-stage analysis is at least part of the search –

some cataloging or aggregation is required -- it raises the possibility that Carpenter searches

require a similar range of steps.

V. What Carpenter Says About Timing – And What It Doesn’t Say

That brings us, finally, to Carpenter itself. The Carpenter majority opinion gives us a few clues

on the timing of when a search at least starts. But the clues don’t seem particularly precise or

consistent. And while they talk about when the search may start, they don’t seem to tell us when

the search ends.

That’s not necessarily criticism of the majority, to be clear. The timing question wasn’t presented

to the Justices because it didn’t matter in that case. But if we’re looking ahead to how to apply

Carpenter, the timing clues left in the opinion start to matter.

So let’s take a look. Some language in the majority opinion say that a search occurs when the

government “accesses” a database that contains the relevant records. To me, accessing seems to

mean looking through the database to get useful information. Here are a few examples:

(1) “This case presents the question whether the Government conducts a search under the

Fourth Amendment when it accesses historical cell phone records that provide a

comprehensive chronicle of the user’s past movements.”

(2) “Allowing government access to cell-site records contravenes that expectation.”

(3) “With just the click of a button, the Government can access each carrier’s deep

repository of historical location information at practically no expense.”

(4) “Accordingly, when the Government accessed CSLI from the wireless carriers, it

invaded Carpenter’s reasonable expectation of privacy in the whole of his physical

movements.”

(5) “We decline to grant the state unrestricted access to a wireless carrier’s database of

physical location information.”

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Other parts of the opinion refer to the relevant stage as “acquiring” the records instead of

“accessing” them. The word “acquiring” can have different meanings. On the whole, though, that

word seems to suggest a relatively early stage of merely coming into possession of the records

even if they are not actually examined or queried.

Here are some of the passages that refer to acquiring or similar language instead of accessing:

(1) “The case before us involves the Government’s acquisition of wireless carrier cell-

site records revealing the location of Carpenter’s cell phone whenever it made or

received calls.”

(2) “The Government’s acquisition of the cell-site records was a search within the meaning

of the Fourth Amendment.”

(3) “Having found that the acquisition of Carpenter’s CSLI was a search, we also conclude

that the Government must generally obtain a warrant supported by probable cause before

acquiring such records.”

(4) “The Government’s acquisition of the cell-site records here was a search under that

Amendment.”

(5) “Before compelling a wireless carrier to turn over a subscriber’s CSLI, the

Government’s obligation is a familiar one—get a warrant.”

So which is the search, acquiring the records or accessing them? Possessing them or making use

of them? I’m not entirely sure.

Beyond the possible acquisition/access distinction, there are two important additional uncertainties

on how Carpenter deals with the timing.

First, Carpenter assumes that all of the records have been combined into a database that can be

queried to get all the relevant information. It doesn’t say how the law should apply when the

relevant information has to be obtained from combining databases. Recall stages 6 and 7 above in

Part III. The first database didn’t actually have the locations of the cell towers. It had only raw

numbers. The second database was needed to link site numbers to actual places.

I wonder, in this hypothetical, would just the first database count as “location information” for

Carpenter purposes? Is either acquiring or accessing that database alone a search? There is no

actual “location” information in that database. It is just meaningless numbers. But it’s a good step

towards having location information. Is that enough? Does it matter how easy or hard it is to

combine those meaningless numbers with the location information? For example, does it matter

if the second database file, with the links between site numbers and location, is a closely-guarded

secret versus if it is something that can be looked up on the public web or is given out relatively

freely by the provider? You can see why it matters. Going back to the eight stages of surveillance

in Part III, the answers tell you when a search starts: Does it begin at stage 4, 5, 6, 7, or 8? It’s

hard to say, I think.

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The next uncertainty is when the search ends. Let’s say you identify a stage when a search starts.

Does the search end there, too? Or is the search ongoing for some set of the stages of surveillance?

This isn’t a hard problem in traditional Fourth Amendment law because you would traditionally

say that once data has been searched, further examination is not a search again. As the Supreme

Court stated in Illinois v. Andreas, 463 U.S. 765, 771–72 (1983), “once the police are lawfully in

a position to observe an item firsthand, its owner’s privacy interest in that item is lost.”

Observation can be a search, but searching once eliminates the expectation of privacy. Or at least

that’s the traditional view of the Supreme Court’s caselaw.

But does Carpenter change that? If Carpenter searches are about accessing information, you

might get new searches at different stages of the surveillance as more information is obtained. You

might have one search at one stage and a second or third search later. If the government has a

warrant at the outset, of course, the warrant should suffice for all the steps. A warrant authorizes

as many distinct searches as are needed to search the described place for the described evidence.

But what happens if an exception to the warrant requirement applies at one step but not another?

Say you can get to a particular stage of surveillance where a search has occurred but a warrant was

not necessary because an exception to the warrant requirement applied such as exigent

circumstances. Next say that the exception no longer applies going forward. Are subsequent stages

of surveillance new searches that now require a warrant to execute? Or is the search over from the

earlier stage of surveillance so the subsequent stage can occur without Fourth Amendment

oversight?

VI. Four Closing Hypotheticals

Here are a four hypotheticals to bring out these uncertainties and make the issues concrete. To be

clear, these aren’t exam questions where I know the best answers and I’m wondering who among

you readers can find them. Rather, these are uncertain issues under Carpenter that I’m not sure

how courts will answer. I’m curious to know what you think of them.

(1) “Has David Ever Been To California?” Say David has been charged with killing a man in

New York. The exact time of the death is unclear, but the crime is thought to have happened in

recent weeks. David’s alibi is that he was in California all of the last month and that he could not

have committed the crime in New York. Investigators want a representative from David’s cell

provider to testify at trial to answer just one question: Whether, based on a review of the last month

of David’s CSLI records, David’s phone connected to any cell sites in California at any time in the

last month. Is obtaining that testimony a Fourth Amendment search that first requires a warrant,

and if so what kind of probable cause showing is required for it?

(2) “Just Tell Me If When There Was a Match.” Imagine the government is investigating a robbery

conspiracy. Investigators want the provider to disclose the times and dates in the last year when

the cell phones used by the four suspects were connected to the same cell tower within 15 minutes

of each other. Investigators don’t want to know where the cell sites were located. They only want

a list of times, if any, when all four cell phones were using the same cell site (without knowing

where that was). An employee at the provider takes its databases and combine them to look for

matches. He responds to the government with a list of times, and those times happen to match to

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the dates of known robberies. Was it a Fourth Amendment search to obtain that list of times? If

so, do all of them have standing to challenge the search?

(3) “The Emergency Passed.” The police are investigating an ongoing kidnapping. In an effort

to find out where the kidnapper is, the police ask the suspect’s cellular provider to disclose the

whereabouts of the suspect’s phone for the last month. The provider does so without a warrant in

light of the exigent circumstances of needing to find the kidnapper right away. The government

gets the location information covering one month under the exigent circumstances exception to the

warrant requirement. The kidnapper is not found, however. A year later, investigators in a different

case come to think that the same suspect may have also committed a string of burglaries around

the same time. They want to examine the location information that was originally obtained to find

the kidnapper, but this time they want to analyze the records to see if the locations matched the

burglaries. Is this later examination another search, and if so does it require a warrant?

(4) “We’ll Query the Database in An Emergency” Congress enacts a terrorist surveillance

program that requires every cellular provider to hand over all CSLI to the government once a week.

The government is required to save all the CSLI files for all time without looking at any of the

data. When an emergency amounting to exigent circumstances occurs, however, the government

can query the CSLI database to obtain location records relating to particular suspects. Has a search

occurred if no emergency has occurred yet and the records have been obtained but not opened or

analyzed?