WASHINGTON -- Cellphones and smartphones generally cannot be searched by police without a warrant during arrests, the Supreme Court ruled unanimously Wednesday in a major clash between privacy and technology.
Ruling on two cases from California and Massachusetts, the justices acknowledged both a right to privacy and a need to investigate crimes. But they came down squarely on the side of privacy rights.
"We cannot deny that our decision today will have an impact on the ability of law enforcement to combat crime," Chief Justice John Roberts wrote for the court. "Privacy comes at a cost."
The court struck down an extensive smartphone search in California that had been upheld by the state Court of Appeals, as well as a more limited probe of an old flip-top cellphone in Massachusetts that a federal judge had thrown out.
The result was a ruling that police cannot seek what they believe is relevant to the crime without getting a warrant. Currently, police can search the person under arrest and whatever is within reach to find weapons and preserve evidence.
The justices noted that vast amounts of sensitive data on modern smartphones raise new privacy concerns.
In the past two years, the court has ruled that police can swab a suspect's cheek for DNA to put into an unsolved crimes database, as well as conduct strip searches of prisoners without reasonable suspicion.
But the justices also have said police need a warrant to attach a GPS device to a suspect's car, to obtain blood from a drunken driver who refuses a breathalyzer test, and to bring a drug-sniffing dog up to the door of a suspect's house.
The cellphone cases may be just a precursor to more expansive and potentially explosive high court inquiries. Among them: an examination of the National Security Agency's phone and computer surveillance methods, on which two federal district courts recently diverged.
The two cellphone cases, heard back-to-back in April, involved different crimes, different responses and different lower-court rulings. What joined them was the fact that police searched cellphones without first obtaining warrants.
A California court upheld David Riley's conviction on gang-related weapons offenses that police uncovered after stopping his car for expired tags, finding guns under the hood and then discovering incriminating photos and video on his smartphone.
In Massachusetts, a federal appeals court threw out Brima Wurie's conviction after a specifically targeted search of his old-fashioned flip-phone following a street arrest led police to find a cache of drugs and weapons at his home.
Because the California search was extensive and the Massachusetts search aimed only at incoming calls and addresses, both cases appeared ripe for reversal. But with appeals courts divided on the issue of cellphone searches, the justices also were being asked to devise bright-line rules for police to follow.
That's particularly true because technology is advancing, creating new Fourth Amendment puzzles for police to solve. Nine in 10 adults in the U.S. own cellphones, more than half of them smartphones. Eight in 10 use those phones to send text messages; more than half send or receive e-mail, download applications, or access the Internet.
Combine that data with the estimated 12.2 million arrests made nationwide in 2012 — not including citations for traffic violations — and you have a potential perfect storm of cellphone searches.
Find @richardjwolf on Twitter.