Riley v. Cal. United States

(Slip Opinion) OCTOBER TERM, 2013 1

Syllabus

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is

being done in connection with this case, at the time the opinion is issued.

The syllabus constitutes no part of the opinion of the Court but has been

prepared by the Reporter of Decisions for the convenience of the reader.

See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

Syllabus

RILEY v. CALIFORNIA

CERTIORARI TO THE COURT OF APPEAL OF CALIFORNIA,

FOURTH APPELLATE DISTRICT, DIVISION ONE

No. 13–132. Argued April 29, 2014—Decided June 25, 2014*

In No. 13–132, petitioner Riley was stopped for a traffic violation,

which eventually led to his arrest on weapons charges. An officer

searching Riley incident to the arrest seized a cell phone from Riley’s

pants pocket. The officer accessed information on the phone and no-

ticed the repeated use of a term associated with a street gang. At the

police station two hours later, a detective specializing in gangs fur-

ther examined the phone’s digital contents. Based in part on photo-

graphs and videos that the detective found, the State charged Riley

in connection with a shooting that had occurred a few weeks earlier

and sought an enhanced sentence based on Riley’s gang membership.

Riley moved to suppress all evidence that the police had obtained

from his cell phone. The trial court denied the motion, and Riley was

convicted. The California Court of Appeal affirmed.

In No. 13–212, respondent Wurie was arrested after police ob-

served him participate in an apparent drug sale. At the police sta-

tion, the officers seized a cell phone from Wurie’s person and noticed

that the phone was receiving multiple calls from a source identified

as “my house” on its external screen. The officers opened the phone,

accessed its call log, determined the number associated with the “my

house” label, and traced that number to what they suspected was

Wurie’s apartment. They secured a search warrant and found drugs,

a firearm and ammunition, and cash in the ensuing search. Wurie

was then charged with drug and firearm offenses. He moved to sup-

press the evidence obtained from the search of the apartment. The

District Court denied the motion, and Wurie was convicted. The

——————

* Together with No. 13–212, United States v. Wurie, on certiorari to

the United States Court of Appeals for the First Circuit.

2 RILEY v. CALIFORNIA

Syllabus

First Circuit reversed the denial of the motion to suppress and vacat-

ed the relevant convictions.

Held: The police generally may not, without a warrant, search digital

information on a cell phone seized from an individual who has been

arrested. Pp. 5–28.

(a) A warrantless search is reasonable only if it falls within a spe-

cific exception to the Fourth Amendment’s warrant requirement. See

Kentucky v. King, 563 U. S. ___, ___. The well-established exception

at issue here applies when a warrantless search is conducted incident

to a lawful arrest.

Three related precedents govern the extent to which officers may

search property found on or near an arrestee. Chimel v. California,

395 U. S. 752, requires that a search incident to arrest be limited to

the area within the arrestee’s immediate control, where it is justified

by the interests in officer safety and in preventing evidence destruc-

tion. In United States v. Robinson, 414 U. S. 218, the Court applied

the Chimel analysis to a search of a cigarette pack found on the ar-

restee’s person. It held that the risks identified in Chimel are pre-

sent in all custodial arrests, 414 U. S., at 235, even when there is no

specific concern about the loss of evidence or the threat to officers in a

particular case, id., at 236. The trilogy concludes with Arizona v.

Gant, 556 U. S. 332, which permits searches of a car where the ar-

restee is unsecured and within reaching distance of the passenger

compartment, or where it is reasonable to believe that evidence of the

crime of arrest might be found in the vehicle, id., at 343. Pp. 5–8.

(b) The Court declines to extend Robinson’s categorical rule to

searches of data stored on cell phones. Absent more precise guidance

from the founding era, the Court generally determines whether to ex-

empt a given type of search from the warrant requirement “by as-

sessing, on the one hand, the degree to which it intrudes upon an in-

dividual’s privacy and, on the other, the degree to which it is needed

for the promotion of legitimate governmental interests.” Wyoming v.

Houghton, 526 U. S. 295, 300. That balance of interests supported

the search incident to arrest exception in Robinson. But a search of

digital information on a cell phone does not further the government

interests identified in Chimel, and implicates substantially greater

individual privacy interests than a brief physical search. Pp. 8–22.

(1) The digital data stored on cell phones does not present either

Chimel risk. Pp. 10–15.

(i) Digital data stored on a cell phone cannot itself be used as a

weapon to harm an arresting officer or to effectuate the arrestee’s es-

cape. Officers may examine the phone’s physical aspects to ensure

that it will not be used as a weapon, but the data on the phone can

endanger no one. To the extent that a search of cell phone data

Cite as: 573 U. S. ____ (2014) 3

Syllabus

might warn officers of an impending danger, e.g., that the arrestee’s

confederates are headed to the scene, such a concern is better ad-

dressed through consideration of case-specific exceptions to the war-

rant requirement, such as exigent circumstances. See, e.g., Warden,

Md. Penitentiary v. Hayden, 387 U. S. 294, 298–299. Pp. 10–12.

(ii) The United States and California raise concerns about the

destruction of evidence, arguing that, even if the cell phone is physi-

cally secure, information on the cell phone remains vulnerable to re-

mote wiping and data encryption. As an initial matter, those broad

concerns are distinct from Chimel’s focus on a defendant who re-

sponds to arrest by trying to conceal or destroy evidence within his

reach. The briefing also gives little indication that either problem is

prevalent or that the opportunity to perform a search incident to ar-

rest would be an effective solution. And, at least as to remote wiping,

law enforcement currently has some technologies of its own for com-

batting the loss of evidence. Finally, law enforcement’s remaining

concerns in a particular case might be addressed by responding in a

targeted manner to urgent threats of remote wiping, see Missouri v.

McNeely, 569 U. S. ___, ___, or by taking action to disable a phone’s

locking mechanism in order to secure the scene, see Illinois v. McAr-

thur, 531 U. S. 326, 331–333. Pp. 12–15.

(2) A conclusion that inspecting the contents of an arrestee’s

pockets works no substantial additional intrusion on privacy beyond

the arrest itself may make sense as applied to physical items, but

more substantial privacy interests are at stake when digital data is

involved. Pp. 15–22.

(i) Cell phones differ in both a quantitative and a qualitative

sense from other objects that might be carried on an arrestee’s per-

son. Notably, modern cell phones have an immense storage capacity.

Before cell phones, a search of a person was limited by physical reali-

ties and generally constituted only a narrow intrusion on privacy.

But cell phones can store millions of pages of text, thousands of pic-

tures, or hundreds of videos. This has several interrelated privacy

consequences. First, a cell phone collects in one place many distinct

types of information that reveal much more in combination than any

isolated record. Second, the phone’s capacity allows even just one

type of information to convey far more than previously possible.

Third, data on the phone can date back for years. In addition, an el-

ement of pervasiveness characterizes cell phones but not physical

records. A decade ago officers might have occasionally stumbled

across a highly personal item such as a diary, but today many of the

more than 90% of American adults who own cell phones keep on their

person a digital record of nearly every aspect of their lives. Pp. 17–

21.

4 RILEY v. CALIFORNIA

Syllabus

(ii) The scope of the privacy interests at stake is further com-

plicated by the fact that the data viewed on many modern cell phones

may in fact be stored on a remote server. Thus, a search may extend

well beyond papers and effects in the physical proximity of an ar-

restee, a concern that the United States recognizes but cannot defini-

tively foreclose. Pp. 21–22.

(c) Fallback options offered by the United States and California are

flawed and contravene this Court’s general preference to provide

clear guidance to law enforcement through categorical rules. See

Michigan v. Summers, 452 U. S. 692, 705, n. 19. One possible rule is

to import the Gant standard from the vehicle context and allow a

warrantless search of an arrestee’s cell phone whenever it is reason-

able to believe that the phone contains evidence of the crime of ar-

rest. That proposal is not appropriate in this context, and would

prove no practical limit at all when it comes to cell phone searches.

Another possible rule is to restrict the scope of a cell phone search to

information relevant to the crime, the arrestee’s identity, or officer

safety. That proposal would again impose few meaningful con-

straints on officers. Finally, California suggests an analogue rule,

under which officers could search cell phone data if they could have

obtained the same information from a pre-digital counterpart. That

proposal would allow law enforcement to search a broad range of

items contained on a phone even though people would be unlikely to

carry such a variety of information in physical form, and would

launch courts on a difficult line-drawing expedition to determine

which digital files are comparable to physical records. Pp. 22–25.

(d) It is true that this decision will have some impact on the ability

of law enforcement to combat crime. But the Court’s holding is not

that the information on a cell phone is immune from search; it is that

a warrant is generally required before a search. The warrant re-

quirement is an important component of the Court’s Fourth Amend-

ment jurisprudence, and warrants may be obtained with increasing

efficiency. In addition, although the search incident to arrest excep-

tion does not apply to cell phones, the continued availability of the ex-

igent circumstances exception may give law enforcement a justifica-

tion for a warrantless search in particular cases. Pp. 25–27.

No. 13–132, reversed and remanded; No. 13–212, 728 F. 3d 1, affirmed.

ROBERTS, C. J., delivered the opinion of the Court, in which SCALIA,

KENNEDY, THOMAS, GINSBURG, BREYER, SOTOMAYOR, and KAGAN, JJ.,

joined. ALITO, J., filed an opinion concurring in part and concurring in

the judgment.

Cite as: 573 U. S. ____ (2014) 1

Opinion of the Court

NOTICE: This opinion is subject to formal revision before publication in the

preliminary print of the United States Reports. Readers are requested to

notify the Reporter of Decisions, Supreme Court of the United States, Wash-

ington, D. C. 20543, of any typographical or other formal errors, in order

that corrections may be made before the preliminary print goes to press.

SUPREME COURT OF THE UNITED STATES

_________________

Nos. 13–132 and 13–212

_________________

DAVID LEON RILEY, PETITIONER

13–132 v.

CALIFORNIA

ON WRIT OF CERTIORARI TO THE COURT OF APPEAL OF CALI-

FORNIA, FOURTH APPELLATE DISTRICT, DIVISION ONE

UNITED STATES, PETITIONER

13–212 v.

BRIMA WURIE

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF

APPEALS FOR THE FIRST CIRCUIT

[June 25, 2014]

CHIEF JUSTICE ROBERTS delivered the opinion of the

Court.

These two cases raise a common question: whether the

police may, without a warrant, search digital information

on a cell phone seized from an individual who has been

arrested.

I

A

In the first case, petitioner David Riley was stopped by a

police officer for driving with expired registration tags. In

the course of the stop, the officer also learned that Riley’s

license had been suspended. The officer impounded Ri-

ley’s car, pursuant to department policy, and another

2 RILEY v. CALIFORNIA

Opinion of the Court

officer conducted an inventory search of the car. Riley was

arrested for possession of concealed and loaded firearms

when that search turned up two handguns under the car’s

hood. See Cal. Penal Code Ann. §§12025(a)(1), 12031(a)(1)

(West 2009).

An officer searched Riley incident to the arrest and

found items associated with the “Bloods” street gang. He

also seized a cell phone from Riley’s pants pocket. Accord-

ing to Riley’s uncontradicted assertion, the phone was a

“smart phone,” a cell phone with a broad range of other

functions based on advanced computing capability, large

storage capacity, and Internet connectivity. The officer

accessed information on the phone and noticed that some

words (presumably in text messages or a contacts list)

were preceded by the letters “CK”—a label that, he be-

lieved, stood for “Crip Killers,” a slang term for members

of the Bloods gang.

At the police station about two hours after the arrest, a

detective specializing in gangs further examined the con-

tents of the phone. The detective testified that he “went

through” Riley’s phone “looking for evidence, because . . .

gang members will often video themselves with guns or

take pictures of themselves with the guns.” App. in No.

13–132, p. 20. Although there was “a lot of stuff ” on the

phone, particular files that “caught [the detective’s] eye”

included videos of young men sparring while someone

yelled encouragement using the moniker “Blood.” Id., at

11–13. The police also found photographs of Riley stand-

ing in front of a car they suspected had been involved in a

shooting a few weeks earlier.

Riley was ultimately charged, in connection with that

earlier shooting, with firing at an occupied vehicle, assault

with a semiautomatic firearm, and attempted murder.

The State alleged that Riley had committed those crimes

for the benefit of a criminal street gang, an aggravating

factor that carries an enhanced sentence. Compare Cal.

Cite as: 573 U. S. ____ (2014) 3

Opinion of the Court

Penal Code Ann. §246 (2008) with §186.22(b)(4)(B) (2014).

Prior to trial, Riley moved to suppress all evidence that

the police had obtained from his cell phone. He contended

that the searches of his phone violated the Fourth

Amendment, because they had been performed without a

warrant and were not otherwise justified by exigent cir-

cumstances. The trial court rejected that argument. App.

in No. 13–132, at 24, 26. At Riley’s trial, police officers

testified about the photographs and videos found on the

phone, and some of the photographs were admitted into

evidence. Riley was convicted on all three counts and

received an enhanced sentence of 15 years to life in prison.

The California Court of Appeal affirmed. No. D059840

(Cal. App., Feb. 8, 2013), App. to Pet. for Cert. in No. 13–

132, pp. 1a–23a. The court relied on the California Su-

preme Court’s decision in People v. Diaz, 51 Cal. 4th 84,

244 P. 3d 501 (2011), which held that the Fourth Amend-

ment permits a warrantless search of cell phone data

incident to an arrest, so long as the cell phone was imme-

diately associated with the arrestee’s person. See id., at

93, 244 P. 3d, at 505–506.

The California Supreme Court denied Riley’s petition for

review, App. to Pet. for Cert. in No. 13–132, at 24a, and we

granted certiorari, 571 U. S. ___ (2014).

B

In the second case, a police officer performing routine

surveillance observed respondent Brima Wurie make an

apparent drug sale from a car. Officers subsequently

arrested Wurie and took him to the police station. At the

station, the officers seized two cell phones from Wurie’s

person. The one at issue here was a “flip phone,” a kind of

phone that is flipped open for use and that generally has a

smaller range of features than a smart phone. Five to ten

minutes after arriving at the station, the officers noticed

that the phone was repeatedly receiving calls from a

4 RILEY v. CALIFORNIA

Opinion of the Court

source identified as “my house” on the phone’s external

screen. A few minutes later, they opened the phone and

saw a photograph of a woman and a baby set as the

phone’s wallpaper. They pressed one button on the phone

to access its call log, then another button to determine the

phone number associated with the “my house” label. They

next used an online phone directory to trace that phone

number to an apartment building.

When the officers went to the building, they saw Wurie’s

name on a mailbox and observed through a window a

woman who resembled the woman in the photograph on

Wurie’s phone. They secured the apartment while obtain-

ing a search warrant and, upon later executing the war-

rant, found and seized 215 grams of crack cocaine, mari-

juana, drug paraphernalia, a firearm and ammunition, and

cash.

Wurie was charged with distributing crack cocaine,

possessing crack cocaine with intent to distribute, and

being a felon in possession of a firearm and ammunition.

See 18 U. S. C. §922(g); 21 U. S. C. §841(a). He moved to

suppress the evidence obtained from the search of the

apartment, arguing that it was the fruit of an unconstitu-

tional search of his cell phone. The District Court denied

the motion. 612 F. Supp. 2d 104 (Mass. 2009). Wurie was

convicted on all three counts and sentenced to 262 months

in prison.

A divided panel of the First Circuit reversed the denial

of Wurie’s motion to suppress and vacated Wurie’s convic-

tions for possession with intent to distribute and posses-

sion of a firearm as a felon. 728 F. 3d 1 (2013). The court

held that cell phones are distinct from other physical

possessions that may be searched incident to arrest with-

out a warrant, because of the amount of personal data cell

phones contain and the negligible threat they pose to law

enforcement interests. See id., at 8–11.

We granted certiorari. 571 U. S. ___ (2014).

Cite as: 573 U. S. ____ (2014) 5

Opinion of the Court

II

The Fourth Amendment provides:

“The right of the people to be secure in their per-

sons, houses, papers, and effects, against unreasona-

ble searches and seizures, shall not be violated, and

no Warrants shall issue, but upon probable cause,

supported by Oath or affirmation, and particularly

describing the place to be searched, and the persons or

things to be seized.”

As the text makes clear, “the ultimate touchstone of the

Fourth Amendment is ‘reasonableness.’ ” Brigham City v.

Stuart, 547 U. S. 398, 403 (2006). Our cases have deter-

mined that “[w]here a search is undertaken by law en-

forcement officials to discover evidence of criminal wrong-

doing, . . . reasonableness generally requires the obtaining

of a judicial warrant.” Vernonia School Dist. 47J v. Acton,

515 U. S. 646, 653 (1995). Such a warrant ensures that

the inferences to support a search are “drawn by a neutral

and detached magistrate instead of being judged by the

officer engaged in the often competitive enterprise of

ferreting out crime.” Johnson v. United States, 333 U. S.

10, 14 (1948). In the absence of a warrant, a search is

reasonable only if it falls within a specific exception to the

warrant requirement. See Kentucky v. King, 563 U. S.

___, ___ (2011) (slip op., at 5–6).

The two cases before us concern the reasonableness of a

warrantless search incident to a lawful arrest. In 1914,

this Court first acknowledged in dictum “the right on the

part of the Government, always recognized under English

and American law, to search the person of the accused

when legally arrested to discover and seize the fruits or

evidences of crime.” Weeks v. United States, 232 U. S. 383,

392. Since that time, it has been well accepted that such a

search constitutes an exception to the warrant require-

ment. Indeed, the label “exception” is something of a

6 RILEY v. CALIFORNIA

Opinion of the Court

misnomer in this context, as warrantless searches incident

to arrest occur with far greater frequency than searches

conducted pursuant to a warrant. See 3 W. LaFave,

Search and Seizure §5.2(b), p. 132, and n. 15 (5th ed.

2012).

Although the existence of the exception for such searches

has been recognized for a century, its scope has been de-

bated for nearly as long. See Arizona v. Gant, 556 U. S.

332, 350 (2009) (noting the exception’s “checkered his-

tory”). That debate has focused on the extent to which

officers may search property found on or near the arrestee.

Three related precedents set forth the rules governing

such searches:

The first, Chimel v. California, 395 U. S. 752 (1969), laid

the groundwork for most of the existing search incident to

arrest doctrine. Police officers in that case arrested

Chimel inside his home and proceeded to search his entire

three-bedroom house, including the attic and garage. In

particular rooms, they also looked through the contents of

drawers. Id., at 753–754.

The Court crafted the following rule for assessing the

reasonableness of a search incident to arrest:

“When an arrest is made, it is reasonable for the ar-

resting officer to search the person arrested in order

to remove any weapons that the latter might seek to

use in order to resist arrest or effect his escape. Oth-

erwise, the officer’s safety might well be endangered,

and the arrest itself frustrated. In addition, it is en-

tirely reasonable for the arresting officer to search for

and seize any evidence on the arrestee’s person in or-

der to prevent its concealment or destruction. . . .

There is ample justification, therefore, for a search of

the arrestee’s person and the area ‘within his immedi-

ate control’—construing that phrase to mean the area

from within which he might gain possession of a

Cite as: 573 U. S. ____ (2014) 7

Opinion of the Court

weapon or destructible evidence.” Id., at 762–763.

The extensive warrantless search of Chimel’s home did not

fit within this exception, because it was not needed to

protect officer safety or to preserve evidence. Id., at 763,

768.

Four years later, in United States v. Robinson, 414 U. S.

218 (1973), the Court applied the Chimel analysis in the

context of a search of the arrestee’s person. A police of-

ficer had arrested Robinson for driving with a revoked

license. The officer conducted a patdown search and felt

an object that he could not identify in Robinson’s coat

pocket. He removed the object, which turned out to be a

crumpled cigarette package, and opened it. Inside were 14

capsules of heroin. Id., at 220, 223.

The Court of Appeals concluded that the search was

unreasonable because Robinson was unlikely to have

evidence of the crime of arrest on his person, and because

it believed that extracting the cigarette package and open-

ing it could not be justified as part of a protective search

for weapons. This Court reversed, rejecting the notion

that “case-by-case adjudication” was required to determine

“whether or not there was present one of the reasons

supporting the authority for a search of the person inci-

dent to a lawful arrest.” Id., at 235. As the Court ex-

plained, “[t]he authority to search the person incident to a

lawful custodial arrest, while based upon the need to

disarm and to discover evidence, does not depend on what

a court may later decide was the probability in a particu-

lar arrest situation that weapons or evidence would in fact

be found upon the person of the suspect.” Ibid. Instead, a

“custodial arrest of a suspect based on probable cause is a

reasonable intrusion under the Fourth Amendment; that

intrusion being lawful, a search incident to the arrest

requires no additional justification.” Ibid.

The Court thus concluded that the search of Robinson

8 RILEY v. CALIFORNIA

Opinion of the Court

was reasonable even though there was no concern about

the loss of evidence, and the arresting officer had no spe-

cific concern that Robinson might be armed. Id., at 236.

In doing so, the Court did not draw a line between a

search of Robinson’s person and a further examination of

the cigarette pack found during that search. It merely

noted that, “[h]aving in the course of a lawful search come

upon the crumpled package of cigarettes, [the officer] was

entitled to inspect it.” Ibid. A few years later, the Court

clarified that this exception was limited to “personal prop-

erty . . . immediately associated with the person of the

arrestee.” United States v. Chadwick, 433 U. S. 1, 15

(1977) (200-pound, locked footlocker could not be searched

incident to arrest), abrogated on other grounds by Califor-

nia v. Acevedo, 500 U. S. 565 (1991).

The search incident to arrest trilogy concludes with

Gant, which analyzed searches of an arrestee’s vehicle.

Gant, like Robinson, recognized that the Chimel concerns

for officer safety and evidence preservation underlie the

search incident to arrest exception. See 556 U. S., at 338.

As a result, the Court concluded that Chimel could author-

ize police to search a vehicle “only when the arrestee is

unsecured and within reaching distance of the passenger

compartment at the time of the search.” 556 U. S., at 343.

Gant added, however, an independent exception for a

warrantless search of a vehicle’s passenger compartment

“when it is ‘reasonable to believe evidence relevant to the

crime of arrest might be found in the vehicle.’ ” Ibid.

(quoting Thornton v. United States, 541 U. S. 615, 632

(2004) (SCALIA, J., concurring in judgment)). That excep-

tion stems not from Chimel, the Court explained, but from

“circumstances unique to the vehicle context.” 556 U. S.,

at 343.

III

These cases require us to decide how the search incident

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Opinion of the Court

to arrest doctrine applies to modern cell phones, which are

now such a pervasive and insistent part of daily life that

the proverbial visitor from Mars might conclude they were

an important feature of human anatomy. A smart phone

of the sort taken from Riley was unheard of ten years ago;

a significant majority of American adults now own such

phones. See A. Smith, Pew Research Center, Smartphone

Ownership—2013 Update (June 5, 2013). Even less so-

phisticated phones like Wurie’s, which have already faded

in popularity since Wurie was arrested in 2007, have been

around for less than 15 years. Both phones are based on

technology nearly inconceivable just a few decades ago,

when Chimel and Robinson were decided.

Absent more precise guidance from the founding era, we

generally determine whether to exempt a given type of

search from the warrant requirement “by assessing, on the

one hand, the degree to which it intrudes upon an individ-

ual’s privacy and, on the other, the degree to which it is

needed for the promotion of legitimate governmental

interests.” Wyoming v. Houghton, 526 U. S. 295, 300

(1999). Such a balancing of interests supported the search

incident to arrest exception in Robinson, and a mechanical

application of Robinson might well support the warrant-

less searches at issue here.

But while Robinson’s categorical rule strikes the appro-

priate balance in the context of physical objects, neither of

its rationales has much force with respect to digital con-

tent on cell phones. On the government interest side,

Robinson concluded that the two risks identified in

Chimel—harm to officers and destruction of evidence—are

present in all custodial arrests. There are no comparable

risks when the search is of digital data. In addition, Rob-

inson regarded any privacy interests retained by an indi-

vidual after arrest as significantly diminished by the fact

of the arrest itself. Cell phones, however, place vast quan-

tities of personal information literally in the hands of

10 RILEY v. CALIFORNIA

Opinion of the Court

individuals. A search of the information on a cell phone

bears little resemblance to the type of brief physical search

considered in Robinson.

We therefore decline to extend Robinson to searches of

data on cell phones, and hold instead that officers must

generally secure a warrant before conducting such a

search.

A

We first consider each Chimel concern in turn. In doing

so, we do not overlook Robinson’s admonition that searches

of a person incident to arrest, “while based upon the

need to disarm and to discover evidence,” are reasonable

regardless of “the probability in a particular arrest situa-

tion that weapons or evidence would in fact be found.” 414

U. S., at 235. Rather than requiring the “case-by-case

adjudication” that Robinson rejected, ibid., we ask instead

whether application of the search incident to arrest doc-

trine to this particular category of effects would “untether

the rule from the justifications underlying the Chimel

exception,” Gant, supra, at 343. See also Knowles v. Iowa,

525 U. S. 113, 119 (1998) (declining to extend Robinson to

the issuance of citations, “a situation where the concern

for officer safety is not present to the same extent and the

concern for destruction or loss of evidence is not present at

all”).

1

Digital data stored on a cell phone cannot itself be used

as a weapon to harm an arresting officer or to effectuate

the arrestee’s escape. Law enforcement officers remain

free to examine the physical aspects of a phone to ensure

that it will not be used as a weapon—say, to determine

whether there is a razor blade hidden between the phone

and its case. Once an officer has secured a phone and

eliminated any potential physical threats, however, data

Cite as: 573 U. S. ____ (2014) 11

Opinion of the Court

on the phone can endanger no one.

Perhaps the same might have been said of the cigarette

pack seized from Robinson’s pocket. Once an officer

gained control of the pack, it was unlikely that Robinson

could have accessed the pack’s contents. But unknown

physical objects may always pose risks, no matter how

slight, during the tense atmosphere of a custodial arrest.

The officer in Robinson testified that he could not identify

the objects in the cigarette pack but knew they were not

cigarettes. See 414 U. S., at 223, 236, n. 7. Given that, a

further search was a reasonable protective measure. No

such unknowns exist with respect to digital data. As the

First Circuit explained, the officers who searched Wurie’s

cell phone “knew exactly what they would find therein:

data. They also knew that the data could not harm them.”

728 F. 3d, at 10.

The United States and California both suggest that a

search of cell phone data might help ensure officer safety

in more indirect ways, for example by alerting officers that

confederates of the arrestee are headed to the scene.

There is undoubtedly a strong government interest in

warning officers about such possibilities, but neither the

United States nor California offers evidence to suggest

that their concerns are based on actual experience. The

proposed consideration would also represent a broadening

of Chimel’s concern that an arrestee himself might grab a

weapon and use it against an officer “to resist arrest or

effect his escape.” 395 U. S., at 763. And any such threats

from outside the arrest scene do not “lurk[ ] in all custodial

arrests.” Chadwick, 433 U. S., at 14–15. Accordingly, the

interest in protecting officer safety does not justify dis-

pensing with the warrant requirement across the board.

To the extent dangers to arresting officers may be impli-

cated in a particular way in a particular case, they are

better addressed through consideration of case-specific

exceptions to the warrant requirement, such as the one for

12 RILEY v. CALIFORNIA

Opinion of the Court

exigent circumstances. See, e.g., Warden, Md. Peniten-

tiary v. Hayden, 387 U. S. 294, 298–299 (1967) (“The

Fourth Amendment does not require police officers to

delay in the course of an investigation if to do so would

gravely endanger their lives or the lives of others.”).

2

The United States and California focus primarily on the

second Chimel rationale: preventing the destruction of

evidence.

Both Riley and Wurie concede that officers could have

seized and secured their cell phones to prevent destruction

of evidence while seeking a warrant. See Brief for Peti-

tioner in No. 13–132, p. 20; Brief for Respondent in No.

13–212, p. 41. That is a sensible concession. See Illinois

v. McArthur, 531 U. S. 326, 331–333 (2001); Chadwick,

supra, at 13, and n. 8. And once law enforcement officers

have secured a cell phone, there is no longer any risk that

the arrestee himself will be able to delete incriminating

data from the phone.

The United States and California argue that infor-

mation on a cell phone may nevertheless be vulnerable to

two types of evidence destruction unique to digital data—

remote wiping and data encryption. Remote wiping occurs

when a phone, connected to a wireless network, receives a

signal that erases stored data. This can happen when a

third party sends a remote signal or when a phone is

preprogrammed to delete data upon entering or leaving

certain geographic areas (so-called “geofencing”). See

Dept. of Commerce, National Institute of Standards and

Technology, R. Ayers, S. Brothers, & W. Jansen, Guide-

lines on Mobile Device Forensics (Draft) 29, 31 (SP 800–

101 Rev. 1, Sept. 2013) (hereinafter Ayers). Encryption is

a security feature that some modern cell phones use in

addition to password protection. When such phones lock,

data becomes protected by sophisticated encryption that

Cite as: 573 U. S. ____ (2014) 13

Opinion of the Court

renders a phone all but “unbreakable” unless police know

the password. Brief for United States as Amicus Curiae in

No. 13–132, p. 11.

As an initial matter, these broader concerns about the

loss of evidence are distinct from Chimel’s focus on a

defendant who responds to arrest by trying to conceal or

destroy evidence within his reach. See 395 U. S., at 763–

764. With respect to remote wiping, the Government’s

primary concern turns on the actions of third parties who

are not present at the scene of arrest. And data encryp-

tion is even further afield. There, the Government focuses

on the ordinary operation of a phone’s security features,

apart from any active attempt by a defendant or his asso-

ciates to conceal or destroy evidence upon arrest.

We have also been given little reason to believe that

either problem is prevalent. The briefing reveals only a

couple of anecdotal examples of remote wiping triggered

by an arrest. See Brief for Association of State Criminal

Investigative Agencies et al. as Amici Curiae in No. 13–

132, pp. 9–10; see also Tr. of Oral Arg. in No. 13–132,

p. 48. Similarly, the opportunities for officers to search a

password-protected phone before data becomes encrypted

are quite limited. Law enforcement officers are very

unlikely to come upon such a phone in an unlocked state

because most phones lock at the touch of a button or, as a

default, after some very short period of inactivity. See,

e.g., iPhone User Guide for iOS 7.1 Software 10 (2014)

(default lock after about one minute). This may explain

why the encryption argument was not made until the

merits stage in this Court, and has never been considered

by the Courts of Appeals.

Moreover, in situations in which an arrest might trigger

a remote-wipe attempt or an officer discovers an unlocked

phone, it is not clear that the ability to conduct a warrant-

less search would make much of a difference. The need to

effect the arrest, secure the scene, and tend to other press-

14 RILEY v. CALIFORNIA

Opinion of the Court

ing matters means that law enforcement officers may well

not be able to turn their attention to a cell phone right

away. See Tr. of Oral Arg. in No. 13–132, at 50; see also

Brief for United States as Amicus Curiae in No. 13–132, at

19. Cell phone data would be vulnerable to remote wiping

from the time an individual anticipates arrest to the time

any eventual search of the phone is completed, which

might be at the station house hours later. Likewise, an

officer who seizes a phone in an unlocked state might not

be able to begin his search in the short time remaining

before the phone locks and data becomes encrypted.

In any event, as to remote wiping, law enforcement is

not without specific means to address the threat. Remote

wiping can be fully prevented by disconnecting a phone

from the network. There are at least two simple ways to

do this: First, law enforcement officers can turn the phone

off or remove its battery. Second, if they are concerned

about encryption or other potential problems, they can

leave a phone powered on and place it in an enclosure that

isolates the phone from radio waves. See Ayers 30–31.

Such devices are commonly called “Faraday bags,” after

the English scientist Michael Faraday. They are essen-

tially sandwich bags made of aluminum foil: cheap, light-

weight, and easy to use. See Brief for Criminal Law Pro-

fessors as Amici Curiae 9. They may not be a complete

answer to the problem, see Ayers 32, but at least for now

they provide a reasonable response. In fact, a number of

law enforcement agencies around the country already

encourage the use of Faraday bags. See, e.g., Dept. of

Justice, National Institute of Justice, Electronic Crime

Scene Investigation: A Guide for First Responders 14, 32

(2d ed. Apr. 2008); Brief for Criminal Law Professors as

Amici Curiae 4–6.

To the extent that law enforcement still has specific

concerns about the potential loss of evidence in a particu-

lar case, there remain more targeted ways to address

Cite as: 573 U. S. ____ (2014) 15

Opinion of the Court

those concerns. If “the police are truly confronted with a

‘now or never’ situation,”—for example, circumstances

suggesting that a defendant’s phone will be the target of

an imminent remote-wipe attempt—they may be able to

rely on exigent circumstances to search the phone imme-

diately. Missouri v. McNeely, 569 U. S. ___, ___ (2013)

(slip op., at 10) (quoting Roaden v. Kentucky, 413 U. S.

496, 505 (1973); some internal quotation marks omitted).

Or, if officers happen to seize a phone in an unlocked

state, they may be able to disable a phone’s automatic-lock

feature in order to prevent the phone from locking and

encrypting data. See App. to Reply Brief in No. 13–132, p.

3a (diagramming the few necessary steps). Such a preven-

tive measure could be analyzed under the principles set

forth in our decision in McArthur, 531 U. S. 326, which

approved officers’ reasonable steps to secure a scene to

preserve evidence while they awaited a warrant. See id.,

at 331–333.

B

The search incident to arrest exception rests not only on

the heightened government interests at stake in a volatile

arrest situation, but also on an arrestee’s reduced privacy

interests upon being taken into police custody. Robinson

focused primarily on the first of those rationales. But it

also quoted with approval then-Judge Cardozo’s account of

the historical basis for the search incident to arrest excep-

tion: “Search of the person becomes lawful when grounds

for arrest and accusation have been discovered, and the

law is in the act of subjecting the body of the accused to its

physical dominion.” 414 U. S., at 232 (quoting People v.

Chiagles, 237 N. Y. 193, 197, 142 N. E. 583, 584 (1923));

see also 414 U. S., at 237 (Powell, J., concurring) (“an

individual lawfully subjected to a custodial arrest retains

no significant Fourth Amendment interest in the privacy

of his person”). Put simply, a patdown of Robinson’s cloth-

16 RILEY v. CALIFORNIA

Opinion of the Court

ing and an inspection of the cigarette pack found in his

pocket constituted only minor additional intrusions com-

pared to the substantial government authority exercised

in taking Robinson into custody. See Chadwick, 433 U. S.,

at 16, n. 10 (searches of a person are justified in part by

“reduced expectations of privacy caused by the arrest”).

The fact that an arrestee has diminished privacy inter-

ests does not mean that the Fourth Amendment falls out

of the picture entirely. Not every search “is acceptable

solely because a person is in custody.” Maryland v. King,

569 U. S. ___, ___ (2013) (slip op., at 26). To the contrary,

when “privacy-related concerns are weighty enough” a

“search may require a warrant, notwithstanding the di-

minished expectations of privacy of the arrestee.” Ibid.

One such example, of course, is Chimel. Chimel refused to

“characteriz[e] the invasion of privacy that results from a

top-to-bottom search of a man’s house as ‘minor.’ ” 395

U. S., at 766–767, n. 12. Because a search of the arrestee’s

entire house was a substantial invasion beyond the arrest

itself, the Court concluded that a warrant was required.

Robinson is the only decision from this Court applying

Chimel to a search of the contents of an item found on an

arrestee’s person. In an earlier case, this Court had ap-

proved a search of a zipper bag carried by an arrestee, but

the Court analyzed only the validity of the arrest itself.

See Draper v. United States, 358 U. S. 307, 310–311

(1959). Lower courts applying Robinson and Chimel,

however, have approved searches of a variety of personal

items carried by an arrestee. See, e.g., United States v.

Carrion, 809 F. 2d 1120, 1123, 1128 (CA5 1987) (billfold

and address book); United States v. Watson, 669 F. 2d

1374, 1383–1384 (CA11 1982) (wallet); United States v.

Lee, 501 F. 2d 890, 892 (CADC 1974) (purse).

The United States asserts that a search of all data

stored on a cell phone is “materially indistinguishable”

from searches of these sorts of physical items. Brief for

Cite as: 573 U. S. ____ (2014) 17

Opinion of the Court

United States in No. 13–212, p. 26. That is like saying a

ride on horseback is materially indistinguishable from a

flight to the moon. Both are ways of getting from point A

to point B, but little else justifies lumping them together.

Modern cell phones, as a category, implicate privacy con-

cerns far beyond those implicated by the search of a ciga-

rette pack, a wallet, or a purse. A conclusion that inspect-

ing the contents of an arrestee’s pockets works no

substantial additional intrusion on privacy beyond the

arrest itself may make sense as applied to physical items,

but any extension of that reasoning to digital data has to

rest on its own bottom.

1

Cell phones differ in both a quantitative and a qualita-

tive sense from other objects that might be kept on an

arrestee’s person. The term “cell phone” is itself mislead-

ing shorthand; many of these devices are in fact minicom-

puters that also happen to have the capacity to be used as

a telephone. They could just as easily be called cameras,

video players, rolodexes, calendars, tape recorders, librar-

ies, diaries, albums, televisions, maps, or newspapers.

One of the most notable distinguishing features of mod-

ern cell phones is their immense storage capacity. Before

cell phones, a search of a person was limited by physical

realities and tended as a general matter to constitute only

a narrow intrusion on privacy. See Kerr, Foreword: Ac-

counting for Technological Change, 36 Harv. J. L. & Pub.

Pol’y 403, 404–405 (2013). Most people cannot lug around

every piece of mail they have received for the past several

months, every picture they have taken, or every book or

article they have read—nor would they have any reason to

attempt to do so. And if they did, they would have to drag

behind them a trunk of the sort held to require a search

warrant in Chadwick, supra, rather than a container the

size of the cigarette package in Robinson.

18 RILEY v. CALIFORNIA

Opinion of the Court

But the possible intrusion on privacy is not physically

limited in the same way when it comes to cell phones. The

current top-selling smart phone has a standard capacity of

16 gigabytes (and is available with up to 64 gigabytes).

Sixteen gigabytes translates to millions of pages of text,

thousands of pictures, or hundreds of videos. See Kerr,

supra, at 404; Brief for Center for Democracy & Technol-

ogy et al. as Amici Curiae 7–8. Cell phones couple that

capacity with the ability to store many different types of

information: Even the most basic phones that sell for less

than $20 might hold photographs, picture messages, text

messages, Internet browsing history, a calendar, a thousand-

entry phone book, and so on. See id., at 30; United States

v. Flores-Lopez, 670 F. 3d 803, 806 (CA7 2012). We expect

that the gulf between physical practicability and digital

capacity will only continue to widen in the future.

The storage capacity of cell phones has several interre-

lated consequences for privacy. First, a cell phone collects

in one place many distinct types of information—an ad-

dress, a note, a prescription, a bank statement, a video—

that reveal much more in combination than any isolated

record. Second, a cell phone’s capacity allows even just

one type of information to convey far more than previously

possible. The sum of an individual’s private life can be

reconstructed through a thousand photographs labeled

with dates, locations, and descriptions; the same cannot be

said of a photograph or two of loved ones tucked into a

wallet. Third, the data on a phone can date back to the

purchase of the phone, or even earlier. A person might

carry in his pocket a slip of paper reminding him to call

Mr. Jones; he would not carry a record of all his communi-

cations with Mr. Jones for the past several months, as

would routinely be kept on a phone.1

——————

1 Because the United States and California agree that these cases

involve searches incident to arrest, these cases do not implicate the

Cite as: 573 U. S. ____ (2014) 19

Opinion of the Court

Finally, there is an element of pervasiveness that char-

acterizes cell phones but not physical records. Prior to the

digital age, people did not typically carry a cache of sensi-

tive personal information with them as they went about

their day. Now it is the person who is not carrying a cell

phone, with all that it contains, who is the exception.

According to one poll, nearly three-quarters of smart

phone users report being within five feet of their phones

most of the time, with 12% admitting that they even use

their phones in the shower. See Harris Interactive, 2013

Mobile Consumer Habits Study (June 2013). A decade ago

police officers searching an arrestee might have occasion-

ally stumbled across a highly personal item such as a

diary. See, e.g., United States v. Frankenberry, 387 F. 2d

337 (CA2 1967) (per curiam). But those discoveries were

likely to be few and far between. Today, by contrast, it is

no exaggeration to say that many of the more than 90% of

American adults who own a cell phone keep on their per-

son a digital record of nearly every aspect of their lives—

from the mundane to the intimate. See Ontario v. Quon,

560 U. S. 746, 760 (2010). Allowing the police to scrutinize

such records on a routine basis is quite different from

allowing them to search a personal item or two in the

occasional case.

Although the data stored on a cell phone is distin-

guished from physical records by quantity alone, certain

types of data are also qualitatively different. An Internet

search and browsing history, for example, can be found on

an Internet-enabled phone and could reveal an individu-

al’s private interests or concerns—perhaps a search for

certain symptoms of disease, coupled with frequent visits

to WebMD. Data on a cell phone can also reveal where a

person has been. Historic location information is a stand-

——————

question whether the collection or inspection of aggregated digital

information amounts to a search under other circumstances.

20 RILEY v. CALIFORNIA

Opinion of the Court

ard feature on many smart phones and can reconstruct

someone’s specific movements down to the minute, not

only around town but also within a particular building.

See United States v. Jones, 565 U. S. ___, ___ (2012)

(SOTOMAYOR, J., concurring) (slip op., at 3) (“GPS monitor-

ing generates a precise, comprehensive record of a person’s

public movements that reflects a wealth of detail about

her familial, political, professional, religious, and sexual

associations.”).

Mobile application software on a cell phone, or “apps,”

offer a range of tools for managing detailed information

about all aspects of a person’s life. There are apps for

Democratic Party news and Republican Party news; apps

for alcohol, drug, and gambling addictions; apps for shar-

ing prayer requests; apps for tracking pregnancy symp-

toms; apps for planning your budget; apps for every con-

ceivable hobby or pastime; apps for improving your

romantic life. There are popular apps for buying or selling

just about anything, and the records of such transactions

may be accessible on the phone indefinitely. There are

over a million apps available in each of the two major app

stores; the phrase “there’s an app for that” is now part of

the popular lexicon. The average smart phone user has

installed 33 apps, which together can form a revealing

montage of the user’s life. See Brief for Electronic Privacy

Information Center as Amicus Curiae in No. 13–132, p. 9.

In 1926, Learned Hand observed (in an opinion later

quoted in Chimel) that it is “a totally different thing to

search a man’s pockets and use against him what they

contain, from ransacking his house for everything which

may incriminate him.” United States v. Kirschenblatt, 16

F. 2d 202, 203 (CA2). If his pockets contain a cell phone,

however, that is no longer true. Indeed, a cell phone

search would typically expose to the government far more

than the most exhaustive search of a house: A phone not

only contains in digital form many sensitive records previ-

Cite as: 573 U. S. ____ (2014) 21

Opinion of the Court

ously found in the home; it also contains a broad array of

private information never found in a home in any form—

unless the phone is.

2

To further complicate the scope of the privacy interests

at stake, the data a user views on many modern cell

phones may not in fact be stored on the device itself.

Treating a cell phone as a container whose contents may

be searched incident to an arrest is a bit strained as an

initial matter. See New York v. Belton, 453 U. S. 454, 460,

n. 4 (1981) (describing a “container” as “any object capable

of holding another object”). But the analogy crumbles

entirely when a cell phone is used to access data located

elsewhere, at the tap of a screen. That is what cell

phones, with increasing frequency, are designed to do by

taking advantage of “cloud computing.” Cloud computing

is the capacity of Internet-connected devices to display

data stored on remote servers rather than on the device

itself. Cell phone users often may not know whether

particular information is stored on the device or in the

cloud, and it generally makes little difference. See Brief

for Electronic Privacy Information Center in No. 13–132,

at 12–14, 20. Moreover, the same type of data may be

stored locally on the device for one user and in the cloud

for another.

The United States concedes that the search incident to

arrest exception may not be stretched to cover a search of

files accessed remotely—that is, a search of files stored in

the cloud. See Brief for United States in No. 13–212, at

43–44. Such a search would be like finding a key in a

suspect’s pocket and arguing that it allowed law enforce-

ment to unlock and search a house. But officers searching

a phone’s data would not typically know whether the

information they are viewing was stored locally at the

time of the arrest or has been pulled from the cloud.

22 RILEY v. CALIFORNIA

Opinion of the Court

Although the Government recognizes the problem, its

proposed solutions are unclear. It suggests that officers

could disconnect a phone from the network before search-

ing the device—the very solution whose feasibility it con-

tested with respect to the threat of remote wiping. Com-

pare Tr. of Oral Arg. in No. 13–132, at 50–51, with Tr. of

Oral Arg. in No. 13–212, pp. 13–14. Alternatively, the

Government proposes that law enforcement agencies

“develop protocols to address” concerns raised by cloud

computing. Reply Brief in No. 13–212, pp. 14–15. Proba-

bly a good idea, but the Founders did not fight a revolution

to gain the right to government agency protocols. The

possibility that a search might extend well beyond papers

and effects in the physical proximity of an arrestee is yet

another reason that the privacy interests here dwarf those

in Robinson.

C

Apart from their arguments for a direct extension of

Robinson, the United States and California offer various

fallback options for permitting warrantless cell phone

searches under certain circumstances. Each of the pro-

posals is flawed and contravenes our general preference to

provide clear guidance to law enforcement through cate-

gorical rules. “[I]f police are to have workable rules, the

balancing of the competing interests . . . ‘must in large

part be done on a categorical basis—not in an ad hoc, case-

by-case fashion by individual police officers.’ ” Michigan v.

Summers, 452 U. S. 692, 705, n. 19 (1981) (quoting Duna-

way v. New York, 442 U. S. 200, 219–220 (1979) (White, J.,

concurring)).

The United States first proposes that the Gant standard

be imported from the vehicle context, allowing a warrant-

less search of an arrestee’s cell phone whenever it is rea-

sonable to believe that the phone contains evidence of the

crime of arrest. But Gant relied on “circumstances unique

Cite as: 573 U. S. ____ (2014) 23

Opinion of the Court

to the vehicle context” to endorse a search solely for the

purpose of gathering evidence. 556 U. S., at 343. JUSTICE

SCALIA’s Thornton opinion, on which Gant was based,

explained that those unique circumstances are “a reduced

expectation of privacy” and “heightened law enforcement

needs” when it comes to motor vehicles. 541 U. S., at 631;

see also Wyoming v. Houghton, 526 U. S., at 303–304. For

reasons that we have explained, cell phone searches bear

neither of those characteristics.

At any rate, a Gant standard would prove no practical

limit at all when it comes to cell phone searches. In the

vehicle context, Gant generally protects against searches

for evidence of past crimes. See 3 W. LaFave, Search and

Seizure §7.1(d), at 709, and n. 191. In the cell phone

context, however, it is reasonable to expect that incrimi-

nating information will be found on a phone regardless of

when the crime occurred. Similarly, in the vehicle context

Gant restricts broad searches resulting from minor crimes

such as traffic violations. See id., §7.1(d), at 713, and n.

204. That would not necessarily be true for cell phones. It

would be a particularly inexperienced or unimaginative

law enforcement officer who could not come up with sev-

eral reasons to suppose evidence of just about any crime

could be found on a cell phone. Even an individual pulled

over for something as basic as speeding might well have

locational data dispositive of guilt on his phone. An indi-

vidual pulled over for reckless driving might have evi-

dence on the phone that shows whether he was texting

while driving. The sources of potential pertinent infor-

mation are virtually unlimited, so applying the Gant

standard to cell phones would in effect give “police officers

unbridled discretion to rummage at will among a person’s

private effects.” 556 U. S., at 345.

The United States also proposes a rule that would re-

strict the scope of a cell phone search to those areas of the

phone where an officer reasonably believes that infor-

24 RILEY v. CALIFORNIA

Opinion of the Court

mation relevant to the crime, the arrestee’s identity, or

officer safety will be discovered. See Brief for United

States in No. 13–212, at 51–53. This approach would

again impose few meaningful constraints on officers. The

proposed categories would sweep in a great deal of infor-

mation, and officers would not always be able to discern in

advance what information would be found where.

We also reject the United States’ final suggestion that

officers should always be able to search a phone’s call log,

as they did in Wurie’s case. The Government relies on

Smith v. Maryland, 442 U. S. 735 (1979), which held that

no warrant was required to use a pen register at telephone

company premises to identify numbers dialed by a particu-

lar caller. The Court in that case, however, concluded that

the use of a pen register was not a “search” at all under

the Fourth Amendment. See id., at 745–746. There is no

dispute here that the officers engaged in a search of

Wurie’s cell phone. Moreover, call logs typically contain

more than just phone numbers; they include any identify-

ing information that an individual might add, such as the

label “my house” in Wurie’s case.

Finally, at oral argument California suggested a differ-

ent limiting principle, under which officers could search

cell phone data if they could have obtained the same in-

formation from a pre-digital counterpart. See Tr. of Oral

Arg. in No. 13–132, at 38–43; see also Flores-Lopez, 670

F. 3d, at 807 (“If police are entitled to open a pocket diary

to copy the owner’s address, they should be entitled to

turn on a cell phone to learn its number.”). But the fact

that a search in the pre-digital era could have turned up a

photograph or two in a wallet does not justify a search of

thousands of photos in a digital gallery. The fact that

someone could have tucked a paper bank statement in a

pocket does not justify a search of every bank statement

from the last five years. And to make matters worse, such

an analogue test would allow law enforcement to search a

Cite as: 573 U. S. ____ (2014) 25

Opinion of the Court

range of items contained on a phone, even though people

would be unlikely to carry such a variety of information in

physical form. In Riley’s case, for example, it is implausi-

ble that he would have strolled around with video tapes,

photo albums, and an address book all crammed into his

pockets. But because each of those items has a pre-digital

analogue, police under California’s proposal would be able

to search a phone for all of those items—a significant

diminution of privacy.

In addition, an analogue test would launch courts on a

difficult line-drawing expedition to determine which digi-

tal files are comparable to physical records. Is an e-mail

equivalent to a letter? Is a voicemail equivalent to a

phone message slip? It is not clear how officers could

make these kinds of decisions before conducting a search,

or how courts would apply the proposed rule after the fact.

An analogue test would “keep defendants and judges

guessing for years to come.” Sykes v. United States, 564

U. S. 1, ___ (2011) (SCALIA, J., dissenting) (slip op., at 7)

(discussing the Court’s analogue test under the Armed

Career Criminal Act).

IV

We cannot deny that our decision today will have an

impact on the ability of law enforcement to combat crime.

Cell phones have become important tools in facilitating

coordination and communication among members of crim-

inal enterprises, and can provide valuable incriminating

information about dangerous criminals. Privacy comes at

a cost.

Our holding, of course, is not that the information on a

cell phone is immune from search; it is instead that a

warrant is generally required before such a search, even

when a cell phone is seized incident to arrest. Our cases

have historically recognized that the warrant requirement

is “an important working part of our machinery of gov-

26 RILEY v. CALIFORNIA

Opinion of the Court

ernment,” not merely “an inconvenience to be somehow

‘weighed’ against the claims of police efficiency.” Coolidge

v. New Hampshire, 403 U. S. 443, 481 (1971). Recent

technological advances similar to those discussed here

have, in addition, made the process of obtaining a warrant

itself more efficient. See McNeely, 569 U. S., at ___ (slip

op., at 11–12); id., at ___ (ROBERTS, C. J., concurring in

part and dissenting in part) (slip op., at 8) (describing

jurisdiction where “police officers can e-mail warrant

requests to judges’ iPads [and] judges have signed such

warrants and e-mailed them back to officers in less than

15 minutes”).

Moreover, even though the search incident to arrest

exception does not apply to cell phones, other case-specific

exceptions may still justify a warrantless search of a

particular phone. “One well-recognized exception applies

when ‘ “the exigencies of the situation” make the needs of

law enforcement so compelling that [a] warrantless search

is objectively reasonable under the Fourth Amendment.’ ”

Kentucky v. King, 563 U. S., at ___ (slip op., at 6) (quoting

Mincey v. Arizona, 437 U. S. 385, 394 (1978)). Such exi-

gencies could include the need to prevent the imminent

destruction of evidence in individual cases, to pursue a

fleeing suspect, and to assist persons who are seriously

injured or are threatened with imminent injury. 563

U. S., at ___. In Chadwick, for example, the Court held

that the exception for searches incident to arrest did not

justify a search of the trunk at issue, but noted that “if

officers have reason to believe that luggage contains some

immediately dangerous instrumentality, such as explo-

sives, it would be foolhardy to transport it to the station

house without opening the luggage.” 433 U. S., at 15, n. 9.

In light of the availability of the exigent circumstances

exception, there is no reason to believe that law enforce-

ment officers will not be able to address some of the more

extreme hypotheticals that have been suggested: a suspect

Cite as: 573 U. S. ____ (2014) 27

Opinion of the Court

texting an accomplice who, it is feared, is preparing to

detonate a bomb, or a child abductor who may have infor-

mation about the child’s location on his cell phone. The

defendants here recognize—indeed, they stress—that such

fact-specific threats may justify a warrantless search of

cell phone data. See Reply Brief in No. 13–132, at 8–9;

Brief for Respondent in No. 13–212, at 30, 41. The critical

point is that, unlike the search incident to arrest excep-

tion, the exigent circumstances exception requires a court

to examine whether an emergency justified a warrantless

search in each particular case. See McNeely, supra, at ___

(slip op., at 6).2

* * *

Our cases have recognized that the Fourth Amendment

was the founding generation’s response to the reviled

“general warrants” and “writs of assistance” of the colonial

era, which allowed British officers to rummage through

homes in an unrestrained search for evidence of criminal

activity. Opposition to such searches was in fact one of the

driving forces behind the Revolution itself. In 1761, the

patriot James Otis delivered a speech in Boston denounc-

ing the use of writs of assistance. A young John Adams

was there, and he would later write that “[e]very man of a

crowded audience appeared to me to go away, as I did,

ready to take arms against writs of assistance.” 10 Works

of John Adams 247–248 (C. Adams ed. 1856). According to

Adams, Otis’s speech was “the first scene of the first act of

——————

2 In Wurie’s case, for example, the dissenting First Circuit judge ar-

gued that exigent circumstances could have justified a search of Wurie’s

phone. See 728 F. 3d 1, 17 (2013) (opinion of Howard, J.) (discussing

the repeated unanswered calls from “my house,” the suspected location

of a drug stash). But the majority concluded that the Government had

not made an exigent circumstances argument. See id., at 1. The

Government acknowledges the same in this Court. See Brief for United

States in No. 13–212, p. 28, n. 8.

28 RILEY v. CALIFORNIA

Opinion of the Court

opposition to the arbitrary claims of Great Britain. Then

and there the child Independence was born.” Id., at 248

(quoted in Boyd v. United States, 116 U. S. 616, 625

(1886)).

Modern cell phones are not just another technological

convenience. With all they contain and all they may

reveal, they hold for many Americans “the privacies of

life,” Boyd, supra, at 630. The fact that technology now

allows an individual to carry such information in his hand

does not make the information any less worthy of the

protection for which the Founders fought. Our answer to

the question of what police must do before searching a cell

phone seized incident to an arrest is accordingly simple—

get a warrant.

We reverse the judgment of the California Court of

Appeal in No. 13–132 and remand the case for further

proceedings not inconsistent with this opinion. We affirm

the judgment of the First Circuit in No. 13–212.

It is so ordered.

Cite as: 573 U. S. ____ (2014) 1

Opinion of ALITO, J.

SUPREME COURT OF THE UNITED STATES

_________________

Nos. 13–132 and 13–212

_________________

DAVID LEON RILEY, PETITIONER

13–132 v.

CALIFORNIA

ON WRIT OF CERTIORARI TO THE COURT OF APPEAL OF CALI-

FORNIA, FOURTH APPELLATE DISTRICT, DIVISION ONE

UNITED STATES, PETITIONER

13–212 v.

BRIMA WURIE

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF

APPEALS FOR THE FIRST CIRCUIT

[June 25, 2014]

JUSTICE ALITO, concurring in part and concurring in the

judgment.

I agree with the Court that law enforcement officers, in

conducting a lawful search incident to arrest, must gener-

ally obtain a warrant before searching information stored

or accessible on a cell phone. I write separately to address

two points.

I

A

First, I am not convinced at this time that the ancient

rule on searches incident to arrest is based exclusively (or

even primarily) on the need to protect the safety of arrest-

ing officers and the need to prevent the destruction of

evidence. Cf. ante, at 9. This rule antedates the adoption

of the Fourth Amendment by at least a century. See T.

Clancy, The Fourth Amendment: Its History and Interpre-

tation 340 (2008); T. Taylor, Two Studies in Constitutional

2 RILEY v. CALIFORNIA

Opinion of ALITO, J.

Interpretation 28 (1969); Amar, Fourth Amendment First

Principles, 107 Harv. L. Rev. 757, 764 (1994). In Weeks v.

United States, 232 U. S. 383, 392 (1914), we held that the

Fourth Amendment did not disturb this rule. See also

Taylor, supra, at 45; Stuntz, The Substantive Origins of

Criminal Procedure, 105 Yale L. J. 393, 401 (1995) (“The

power to search incident to arrest—a search of the arrested

suspect’s person . . .—was well established in the mid-

eighteenth century, and nothing in . . . the Fourth

Amendment changed that”). And neither in Weeks nor in

any of the authorities discussing the old common-law rule

have I found any suggestion that it was based exclusively

or primarily on the need to protect arresting officers or to

prevent the destruction of evidence.

On the contrary, when pre-Weeks authorities discussed

the basis for the rule, what was mentioned was the need to

obtain probative evidence. For example, an 1839 case

stated that “it is clear, and beyond doubt, that . . . consta-

bles . . . are entitled, upon a lawful arrest by them of one

charged with treason or felony, to take and detain prop-

erty found in his possession which will form material evi-

dence in his prosecution for that crime.” See Dillon v.

O’Brien, 16 Cox Crim. Cas. 245, 249–251 (1887) (citing

Regina, v. Frost, 9 Car. & P. 129, 173 Eng. Rep. 771)). The

court noted that the origins of that rule “deriv[e] from the

interest which the State has in a person guilty (or reason-

ably believed to be guilty) of a crime being brought to

justice, and in a prosecution, once commenced, being

determined in due course of law.” 16 Cox Crim. Cas., at

249–250. See also Holker v. Hennessey, 141 Mo. 527, 537–

540, 42 S. W. 1090, 1093 (1897).

Two 19th-century treatises that this Court has previ-

ously cited in connection with the origin of the search-

incident-to-arrest rule, see Weeks, supra, at 392, suggest

the same rationale. See F. Wharton, Criminal Pleading

and Practice §60, p. 45 (8th ed. 1880) (“Those arresting a

Cite as: 573 U. S. ____ (2014) 3

Opinion of ALITO, J.

defendant are bound to take from his person any articles

which may be of use as proof in the trial of the offense

with which the defendant is charged”); J. Bishop, Criminal

Procedure §§210–212, p. 127 (2d ed. 1872) (if an arresting

officer finds “about the prisoner’s person, or otherwise in

his possession, either goods or moneys which there is

reason to believe are connected with the supposed crime as

its fruits, or as the instruments with which it was commit-

ted, or as directly furnishing evidence relating to the

transaction, he may take the same, and hold them to be

disposed of as the court may direct”).

What ultimately convinces me that the rule is not closely

linked to the need for officer safety and evidence preser-

vation is that these rationales fail to explain the rule’s

well-recognized scope. It has long been accepted that

written items found on the person of an arrestee may be

examined and used at trial.* But once these items are

——————

* Cf. Hill v. California, 401 U. S. 797, 799–802, and n. 1 (1971) (diary);

Marron v. United States, 275 U. S. 192, 193, 198–199 (1927) (ledger

and bills); Gouled v. United States, 255 U. S. 298, 309 (1921), overruled

on other grounds, Warden, Md. Penitentiary v. Hayden, 387 U. S. 294,

300–301 (1967) (papers); see United States v. Rodriguez, 995 F. 2d 776,

778 (CA7 1993) (address book); United States v. Armendariz–Mata, 949

F. 2d 151, 153 (CA5 1991) (notebook); United States v. Molinaro, 877

F. 2d 1341 (CA7 1989) (wallet); United States v. Richardson, 764 F. 2d

1514, 1527 (CA11 1985) (wallet and papers); United States v. Watson,

669 F. 2d 1374, 1383–1384 (CA11 1982) (documents found in a wallet);

United States v. Castro, 596 F. 2d 674, 677 (CA5 1979), cert. denied,

444 U. S. 963 (1979) (paper found in a pocket); United States v. Jeffers,

520 F. 2d 1256, 1267–1268 (CA7 1975) (three notebooks and meeting

minutes); Bozel v. Hudspeth, 126 F. 2d 585, 587 (CA10 1942) (papers,

circulars, advertising matter, “memoranda containing various names

and addresses”); United States v. Park Avenue Pharmacy, 56 F. 2d 753,

755 (CA2 1932) (“numerous prescriptions blanks” and a check book).

See also 3 W. LaFave, Search and Seizure §5.2(c), p. 144 (5th ed. 2012)

(“Lower courts, in applying Robinson, have deemed evidentiary searches

of an arrested person to be virtually unlimited”); W. Cuddihy, Fourth

Amendment: Origins and Original Meaning 847–848 (1990) (in the pre-

Constitution colonial era, “[a]nyone arrested could expect that not only

4 RILEY v. CALIFORNIA

Opinion of ALITO, J.

taken away from an arrestee (something that obviously

must be done before the items are read), there is no risk

that the arrestee will destroy them. Nor is there any risk

that leaving these items unread will endanger the arrest-

ing officers.

The idea that officer safety and the preservation of

evidence are the sole reasons for allowing a warrantless

search incident to arrest appears to derive from the

Court’s reasoning in Chimel v. California, 395 U. S. 752

(1969), a case that involved the lawfulness of a search of

the scene of an arrest, not the person of an arrestee. As I

have explained, Chimel’s reasoning is questionable, see

Arizona v. Gant, 556 U. S. 332, 361–363 (2009) (ALITO, J.,

dissenting), and I think it is a mistake to allow that rea-

soning to affect cases like these that concern the search of

the person of arrestees.

B

Despite my view on the point discussed above, I agree

that we should not mechanically apply the rule used in the

predigital era to the search of a cell phone. Many cell

phones now in use are capable of storing and accessing a

quantity of information, some highly personal, that no

person would ever have had on his person in hard-copy

form. This calls for a new balancing of law enforcement

and privacy interests.

The Court strikes this balance in favor of privacy inter-

ests with respect to all cell phones and all information

found in them, and this approach leads to anomalies. For

example, the Court’s broad holding favors information in

digital form over information in hard-copy form. Suppose

that two suspects are arrested. Suspect number one has

in his pocket a monthly bill for his land-line phone, and

——————

his surface clothing but his body, luggage, and saddlebags would be

searched”).

Cite as: 573 U. S. ____ (2014) 5

Opinion of ALITO, J.

the bill lists an incriminating call to a long-distance num-

ber. He also has in his a wallet a few snapshots, and one

of these is incriminating. Suspect number two has in his

pocket a cell phone, the call log of which shows a call to

the same incriminating number. In addition, a number of

photos are stored in the memory of the cell phone, and one

of these is incriminating. Under established law, the

police may seize and examine the phone bill and the snap-

shots in the wallet without obtaining a warrant, but under

the Court’s holding today, the information stored in the

cell phone is out.

While the Court’s approach leads to anomalies, I do not

see a workable alternative. Law enforcement officers need

clear rules regarding searches incident to arrest, and it

would take many cases and many years for the courts to

develop more nuanced rules. And during that time, the

nature of the electronic devices that ordinary Americans

carry on their persons would continue to change.

II

This brings me to my second point. While I agree with

the holding of the Court, I would reconsider the question

presented here if either Congress or state legislatures,

after assessing the legitimate needs of law enforcement

and the privacy interests of cell phone owners, enact legis-

lation that draws reasonable distinctions based on catego-

ries of information or perhaps other variables.

The regulation of electronic surveillance provides an

instructive example. After this Court held that electronic

surveillance constitutes a search even when no property

interest is invaded, see Katz v. United States, 389 U. S.

347, 353–359 (1967), Congress responded by enacting Title

III of the Omnibus Crime Control and Safe Streets Act of

1968, 82 Stat. 211. See also 18 U. S. C. §2510 et seq.

Since that time, electronic surveillance has been governed

primarily, not by decisions of this Court, but by the stat-

6 RILEY v. CALIFORNIA

Opinion of ALITO, J.

ute, which authorizes but imposes detailed restrictions on

electronic surveillance. See ibid.

Modern cell phones are of great value for both lawful

and unlawful purposes. They can be used in committing

many serious crimes, and they present new and difficult

law enforcement problems. See Brief for United States in

No. 13–212, pp. 2–3. At the same time, because of the role

that these devices have come to play in contemporary life,

searching their contents implicates very sensitive privacy

interests that this Court is poorly positioned to under-

stand and evaluate. Many forms of modern technology are

making it easier and easier for both government and

private entities to amass a wealth of information about

the lives of ordinary Americans, and at the same time,

many ordinary Americans are choosing to make public

much information that was seldom revealed to outsiders

just a few decades ago.

In light of these developments, it would be very unfor-

tunate if privacy protection in the 21st century were left

primarily to the federal courts using the blunt instrument

of the Fourth Amendment. Legislatures, elected by the

people, are in a better position than we are to assess and

respond to the changes that have already occurred and

those that almost certainly will take place in the future.