Master The Supreme Court held that police generally must obtain a warrant before searching the digital contents of a cell phone seized incident to arrest. with this comprehensive case brief.
Riley v. California is a landmark Fourth Amendment decision that reshaped search-and-seizure law for the digital age. Recognizing that modern cell phones are powerful repositories of personal information, the Supreme Court held that the traditional “search incident to arrest” exception does not authorize warrantless access to a phone’s digital data. The Court aligned constitutional doctrine with technological reality, emphasizing that smartphones differ in both quantitative and qualitative ways from physical containers that officers may inspect during an arrest.
For law students and practitioners, Riley is pivotal because it articulates a clear, administrable rule—get a warrant—while preserving a safety valve for exigent circumstances. It also provides a framework for analyzing how established Fourth Amendment exceptions apply (or do not apply) to emerging technologies, foreshadowing later decisions dealing with digital privacy, such as Carpenter v. United States. Riley thus stands at the intersection of privacy, policing, and technology, illustrating how constitutional protections adapt to new contexts.
573 U.S. 373 (2014) (U.S. Supreme Court)
In San Diego, police stopped David Riley for driving with expired registration tags. After learning Riley’s license was suspended, officers impounded his car and conducted an inventory search, during which they found two handguns. Riley was arrested for weapons offenses. An officer seized Riley’s smartphone from his pants pocket and, without a warrant, examined its contents at the scene, observing indications of gang affiliation. Later at the station, a detective conducted a more thorough review of the phone, accessing photographs and videos that appeared to connect Riley to a recent gang-related shooting. Those digital contents were used to enhance and support criminal charges. In a companion case, United States v. Wurie, Boston police arrested Brima Wurie after observing a drug sale. Officers seized his flip phone and noticed repeated calls from a contact labeled “my house.” Without a warrant, they viewed the call log and traced the number to an address, then obtained a warrant to search the apartment, where they found drugs, cash, and a firearm. The First Circuit suppressed the phone-derived evidence, deepening a split over whether the search-incident-to-arrest doctrine permits warrantless searches of cell phone data. The Supreme Court granted certiorari and consolidated the cases.
Whether, under the Fourth Amendment, police may search the digital contents of a cell phone seized from an arrestee without a warrant under the search-incident-to-arrest exception.
Police generally must secure a warrant before searching digital information on a cell phone seized from an individual who has been lawfully arrested. The traditional search-incident-to-arrest exception does not extend to the phone’s digital data, though exigent circumstances may justify a warrantless search in a particular case.
The Supreme Court unanimously held that the search-incident-to-arrest exception does not authorize warrantless searches of the digital contents of cell phones. Officers must ordinarily obtain a warrant, absent exigent circumstances.
The Court began with the two rationales underpinning search-incident-to-arrest doctrine from Chimel v. California: officer safety and the preservation of evidence. First, officer safety does not justify a digital search. Although an arrestee may conceal weapons in physical containers, the data on a phone cannot itself threaten officers. Officers may physically secure the phone to neutralize any potential hazard, but that does not extend to rummaging through digital files. Second, the government’s evidence-preservation rationale did not support categorical warrantless searches of phone data. Concerns about remote wiping or data encryption were deemed speculative and manageable by less intrusive means (e.g., turning the phone off, removing the battery, using a Faraday bag), and the exigent-circumstances doctrine remains available if specific, articulable facts show an imminent risk of evidence destruction or a pressing need. The Court rejected analogies between a phone and a traditional “container” under United States v. Robinson. Modern phones are not just containers but “minicomputers” that hold a vast and revealing mosaic of information—photos, messages, browsing history, location data, health and financial records—that collectively expose the “privacies of life.” The sheer quantity and qualitative breadth of digital data, coupled with its retrospective and pervasive nature, elevates the privacy interests well beyond those implicated by pocket contents or paper documents. Nor does the possibility that some data may be stored remotely (in the cloud) support warrantless searches; the search-incident doctrine does not authorize fishing expeditions into on-device or cloud-linked accounts simply because the device is on the person of an arrestee. Balancing governmental interests against privacy, the Court adopted a clear rule: officers must get a warrant before searching a phone’s digital content. This rule is administrable, respects core Fourth Amendment values, and leaves room for genuine exigencies (e.g., an immediate threat to life, hot pursuit, or imminent evidence destruction) to justify prompt action without a warrant.
Riley modernized Fourth Amendment doctrine for digital devices, clarifying that personal privacy interests in smartphones are categorically different from physical containers. It sets a bright-line rule that protects vast amounts of sensitive data from warrantless searches during routine arrests, while preserving an exigent-circumstances safety valve. For law students, Riley is essential for understanding how traditional exceptions (search incident to arrest, inventory, exigency) interact with digital technology and for framing analyses in later digital privacy cases, including Carpenter’s treatment of historical cell-site location information. It also guides police practices nationwide, prompting widespread adoption of warrants, Faraday techniques, and data-handling protocols.
Riley involved cell phones, but its reasoning focuses on the unique privacy implications and storage capacity of modern digital devices. Courts have generally applied Riley’s rule to smartphones and other portable digital devices (e.g., tablets) found on the person. The key is that digital data, unlike physical items, is not searchable incident to arrest absent exigent circumstances. Officers may still physically secure the device, but accessing its data ordinarily requires a warrant.
Exigent circumstances are fact-specific and include scenarios like an imminent threat to life, a fleeing suspect, or an objectively reasonable belief that critical evidence will be destroyed before a warrant can be obtained. Examples include locating a kidnapped victim using the phone’s information or addressing a bomb threat. Generalized concerns about remote wiping or encryption are insufficient without particularized facts; officers should mitigate those risks by securing the device while seeking a warrant.
They may physically secure the phone (e.g., seize it, power it down, remove the battery, place it in a Faraday bag) to protect officer safety and preserve evidence. However, Riley bars accessing digital content—such as call logs, texts, photos, apps, or browsing history—without a warrant, unless a true exigency exists. Inventory searches at booking do not authorize reviewing digital data; they are limited to cataloging physical items.
Many courts have applied the good-faith exception to the exclusionary rule for pre-Riley searches conducted in objectively reasonable reliance on then-existing law. Post-Riley, however, officers are on notice that a warrant is generally required, so the good-faith exception will rarely apply to new searches of phone data conducted without a warrant and without exigent circumstances.
Riley limits warrantless searches; it does not define the precise contours of warrants for digital data. A valid warrant must satisfy particularity and probable cause, specifying the device, accounts, data types, and timeframes to be searched. Access to cloud data requires explicit authorization supported by probable cause; officers cannot use the search-incident doctrine to access remote accounts simply because the device is in hand.
No. Riley concerns Fourth Amendment search authority, not Fifth Amendment self-incrimination issues. Lower courts are divided on whether compelling a passcode or biometric unlock is testimonial. The answer often turns on jurisdiction and case-specific facts, including whether the government can describe the contents with sufficient foreknowledge or whether the act of unlocking itself communicates information.
Riley v. California establishes a bright-line Fourth Amendment rule for the digital era: absent exigent circumstances, police must get a warrant to search the data on a cell phone seized incident to arrest. By distinguishing digital information from physical containers, the Court recalibrated the balance between law enforcement needs and personal privacy in a technologically saturated world.
For students and practitioners, Riley offers both doctrinal clarity and analytical tools. It reinforces the centrality of warrant requirements, refines the boundaries of recognized exceptions, and provides a model for evaluating how constitutional protections apply as technology evolves. Its influence reverberates across criminal procedure and digital privacy jurisprudence.