The Supreme Court brought the constitutional right of personal privacy into the digital era Wednesday, ruling unanimously that police may not search a smartphone or similar device without a warrant from a judge.
The decision is the court's most sweeping and surprising criminal law opinion in years, and it is likely to put a significant check on the government's ability to routinely search other types of electronic devices, including laptops and tablets. Some parts of the opinion even cast doubt on the legality of the National Security Agency's routine collection of millions of phone records.
"By recognizing that the digital revolution has transformed our expectations of privacy, today's decision is itself revolutionary," said Steven R. Shapiro, legal director for the American Civil Liberties Union. "We have entered a new world. But our old values still apply and limit the government's ability to rummage through intimate details of our private lives."
Two years ago, in the court's first direct ruling on new types of electronic search devices, the justices unanimously banned the FBI from attaching a GPS device to a car to track the daily travels of a suspected drug dealer. But the justices were divided among themselves and did not issue a single clear opinion.
On Wednesday, however, Chief Justice John G. Roberts Jr. spoke for a unified court and said that because digital devices have transformed how people live, they must also transform the law on privacy.
"Modern cellphones are not just another technological device," he said. "With all they contain and all they may reveal, they hold for many Americans the 'privacies of life.'"
"The term 'cell phone' is itself misleading shorthand; many of these devices are in fact minicomputers," he continued. "They could just as easily be called cameras, video players, rolodexes, calendars, tape recorders, libraries, diaries, albums, televisions, maps or newspapers."
Roberts said such devices can reveal "the sum of an individual's private life [when] reconstructed through a thousand photographs labeled with dates, locations and descriptions."
Until Wednesday, the court's long-standing view was that police were free to search someone who was stopped on the street or in his car and put under arrest. Officers could check a suspect's pockets and examine his possessions, including a wallet, purse and pockets.
The intention was to allow police to protect themselves by finding weapons. But they were also free to collect evidence, such as drugs, stolen goods or papers that might lead to other suspects.
This was known as the "search incident to arrest" rule, and it had been set out in 1973 by then-Justice William H. Rehnquist. A few years later, Roberts came to Washington to be a law clerk for Rehnquist, and in 2005, he succeeded him as chief justice.
In Wednesday's opinion, Roberts said Rehnquist's "categorical rule" for allowing the police to freely search "physical objects" did not make sense when those items were electronic devices.
"Cell phones place vast quantities of personal information literally in the hands of individuals. A search…of a cell phone bears little resemblance to the type of brief physical search" upheld in Rehnquist's 1973 opinion, he wrote. "We therefore decline to extend (the older decision) to searches of data on cell phones and hold instead that officers must generally secure a warrant before conducting such a search."
The unanimous decision came as a surprise to court watchers. During oral arguments in April, some conservative justices appeared unconvinced about making a distinction between searching a suspect's wallet and a searching a smartphone. "I don't see there's much difference," Justice Samuel Alito Jr. commented. Privacy advocates worried that some of the justices did not fully appreciate the breadth of personal data available on 21st century digital devices.
But in the 28-page decision, the court seemed eager to put such concerns to rest, referencing cloud storage technology, geo-fencing security software and apps. It mocked the government's attorneys for arguing that there was no difference between searching a person's pockets and their cellphone.
"That is like saying a ride on horseback is materially indistinguishable from a flight to the moon," Roberts wrote.