On June 25, 2014, the Supreme Court unanimously ruled that police must first obtain a warrant before searching the cell phones of arrested individuals, except in “exigent circumstances.” Chief Justice John Roberts authored the opinion, which held that an individual’s Fourth Amendment right to privacy outweighs the interest of law enforcement in conducting searches of cell phones without a warrant. The decision resolved a split among state and federal courts on the search incident to arrest doctrine (which permits police to search an arrested individual without a warrant) as it applies to cell phones.

The case of Riley v. California as heard before the Supreme Court combined two cases, one involving a smartphone and the other involving a flip phone. In the first case, Riley v. California, the police arrested David Leon Riley, searched his smartphone, and found photographs and videos potentially connecting him to gang activity and an earlier shooting. In the second case, United States v. Wurie, Brima Wurie was arrested for allegedly dealing drugs, and incoming calls on his flip phone helped lead the police to a house used to store drugs and guns.

Roberts wrote that neither of the two justifications for warrantless searches – protecting police officers and preventing the destruction of evidence – applies in the context of cell phones. According to the Court, the justification of protecting police officers falls flat since data on a cell phone cannot be used as a weapon. Roberts was also not persuaded by concerns that criminals could destroy evidence through remote wiping. He pointed out that police have alternatives to a warrantless search in order to prevent the destruction of evidence, including: turning the phone off, removing its battery, or placing the phone in a “Faraday bag,” an aluminum foil bag that blocks radio waves.

The Chief Justice focused on the differences between modern cell phones and other physical items found on arrested individuals to support his argument that modern cell phones “implicate privacy concerns far beyond those implicated by the search of a cigarette pack, a wallet, or a purse.” He cited modern cell phones’ huge storage capacity and how they function as “minicomputers that…could just as easily be called cameras, video players, rolodexes, calendars, tape recorders, libraries, diaries, albums, televisions, maps, or newspapers.” Roberts also noted that data viewed on a phone is frequently not stored on the device itself, but on remote servers, and that officers searching a phone generally do not know the location of data they are viewing.

However, Roberts maintained that exigent circumstances could still justify warrantless searches of cell phones on a case-by-case basis. Such circumstances include: preventing imminent destruction of evidence in individual cases, pursuing a fleeing suspect, and providing assistance to people who are seriously injured or are threatened with imminent injury.

Robert’s opinion is in line with the Court’s stance in the 2012 case United States v. Jones, which held that installing a GPS device on a vehicle and using the device to track the vehicle constitutes a search under the Fourth Amendment.

Justice Samuel Alito concurred in the judgment and agreed with Roberts that the old rule should not be applied mechanically to modern cell phones. However, he made two points that diverged from Roberts’ opinion. First, he disagreed with the idea that the old rule on searches incident to arrest was primarily based on the two justifications of protecting police and preventing destruction of evidence. Second, if Congress or state legislatures pass future legislation on searching cell phones found on arrested individuals, the Court should defer to their judgment.

The Riley opinion recognizes the unique role that cell phones play in modern life (“such a pervasive and insistent part of daily life that the proverbial visitor from Mars might conclude that they were an important feature of the human anatomy”) and that they “hold for many Americans ‘the privacies of life.’”

Special thanks to Tiffany Quach, 2014 summer associate, for her assistance in preparing this post.