Riley v. California

Two consolidated cases — Riley's smartphone, searched after a traffic stop and used to tie him to a shooting, and Wurie's flip phone, whose call log led police to his home — presented the same question: does the search-incident-to-arrest doctrine, which lets officers search items found on an arrestee without a warrant, extend to the digital data on a cell phone?

The search-incident-to-arrest exception rests on two rationales from Chimel: officer safety and prevention of evidence destruction. Neither justifies searching digital data — the data cannot be a weapon, and the risks of remote wiping or encryption can be addressed by securing the phone while seeking a warrant. Where a category of search does not serve the exception's rationales, the default of the Fourth Amendment reasserts itself: get a warrant.

The Court's central move was refusing the analogy to wallets and cigarette packs. A phone's capacity differs quantitatively — millions of pages, thousands of photos, years of correspondence in one place — and qualitatively: internet search history, location records, and app data reveal what no physical container carried, and much of what a phone displays, like cloud-synced files, is not even on the arrestee's person. Searching one, the Chief Justice wrote, bears no resemblance to the pat-down cases; it exposes far more than the exhaustive search of a house.

California's judgment was reversed and the First Circuit's suppression in Wurie affirmed: warrantless phone searches incident to arrest are unconstitutional, subject only to case-by-case exigent circumstances. Riley's quantitative-and-qualitative framing of device data became the foundation Carpenter built on four years later, and courts now cite it well beyond criminal procedure whenever the scope of a device examination is contested.