In two consolidated cases, police searched cell phones seized from David Riley and Brima Wurie after their arrests. Riley’s phone search produced photographs and videos used in his California prosecution; Wurie’s phone displayed a number associated with a residence, and officers used that information to obtain a warrant that led to drug, firearm, and cash seizures. The state and federal courts divided over whether the searches were valid incident to arrest. The Supreme Court held that the search-incident exception does not authorize officers to examine the contents of a phone taken from an arrestee without first obtaining a warrant. The search-incident-to-arrest exception protects officer safety and prevents an arrestee from destroying evidence, but cell-phone data cannot itself endanger officers, and officers can secure a phone while seeking a warrant. Modern phones also contain immense quantities of personal information and may provide access to data stored remotely, making them unlike physical items traditionally searched after arrest. Case-specific exigent circumstances may still justify a warrantless search, but the exception must be evaluated on the facts rather than applied categorically. The Court reversed the California judgment in Riley and affirmed the First Circuit’s judgment in Wurie. Justice Alito concurred in the judgment, emphasizing that legislatures are better positioned to address changing technology and privacy interests.