In its ruling today in Riley v. California, the Supreme Court unanimously established a clear new rule for police-citizen interaction: The police can’t, without a warrant, search the digital information on cell phones they seize from people they arrest. This is a big deal because it means that being arrested for, say, not paying a speeding ticket, will no longer open you up to having your entire life examined by law enforcement. Unlike the satchels and billfolds of yore, people now carry essentially all their private documents with them at all times: address books, financial and medical records, photo albums, diaries, correspondence, and more. To allow police to review all of that information just because they happen to have arrested someone would violate the Fourth Amendment’s protection of personal papers and effects against unreasonable searches and seizures.

If the police have independent probable cause to access someone’s digital information, they can get a warrant. If they don’t, making an arrest shouldn’t give them license to go on a fishing expedition.

What’s really surprising about this ruling is that it’s both broad and unanimous. Sweeping rulings on high-profile subjects tend to split the Court, whether ideologically or, in criminal procedure cases like this one, between formalists and pragmatists. Unanimous rulings, meanwhile, tend to be cautious, splitting the baby in a way that doesn’t significantly change the law. Yet here we have a loud and unified “bright-line rule” that sets a major standard for the digital age. Kudos to the Court—and raspberries to the federal government, which has now had its expansive arguments rejected unanimously 11 times since January 2012.