WASHINGTON — Several Supreme Court justices appeared hesitant Tuesday to tread upon privacy protections in a pair of cases — one involving a Massachusetts drug dealer and the other a California gang member — that will determine whether a suspect’s cellphone is subject to a warrantless police search after an arrest.
At issue is the tension between privacy guaranteed by the Fourth Amendment and modern technology, in which cellphones contain troves of personal data.
“We’re living in a new world,” said Justice Anthony Kennedy. “Someone arrested for a minor crime has their whole existence exposed on this little device.”
The court was asked to address a series of new issues: Can police have access, without a warrant, to a suspect’s text messages, e-mails, photos, and other data on cellphones in the same way they can access a driver’s car trunk following arrest for a traffic offense? Or should the standards for cellphones be different because of the volume of information available?
Justice Antonin Scalia said that if a person is arrested for not wearing a seat belt, ‘‘it seems absurd that you should be able to search that person’s iPhone.’’
In the Massachusetts case, police arrested Brima Wurie in a South Boston parking lot in 2007 for allegedly selling crack cocaine from his car. Through a subsequent search of his cellphone log, police located his residence, where they found other evidence used to convict him of drug and gun crimes.
Wurie was sentenced to more than 21 years in prison. A lower court last year threw out his conviction, ruling that police should not have been allowed to search his phone without a warrant.
The Obama administration urged the Supreme Court to overturn the lower court decision, saying warrantless cellphone searches should be permitted because someone who has been arrested has a reduced expectation of privacy.
Time is of the essence to preserve evidence, the government argued, because cellphone contents can be deleted quickly. Some criminal enterprises have IT departments, ready to remotely wipe out valuable data at a moment’s notice.
In the Wurie case, police saw the suspect’s cellphone ringing as they were booking him. An officer flipped open the phone, pressed a button, learned that the call came from “My House,” and pressed another button for the phone number, said Deputy Solicitor General Michael Dreeben.
“That kind of a search serves valid, time-honored functions . . . of helping to ascertain the identity of the offender,” similar to searching a wallet for identification — a critical fact because Wurie had, moments earlier, lied about his address, Dreeben said.
Wurie’s attorney argued that a cellphone is nothing like a wallet, address book, or another item a person may be carrying while being arrested. Although Wurie’s device was an older model flip phone, smartphones today function as small personal computers that store vast amounts of information such as financial and medical records, e-mail, and Internet browsing history — information typically found in a person’s home and subject to a warrant.
“The court is determining whether or not in 2014 an individual has a reasonable expectation of privacy against government intrusion into a device that carries around an increasingly large percentage of somebody’s personal and private information,” said Judith Mizner, an assistant federal public defender in Boston.
Instead of immediately searching the cellphone, Mizner argued, police should have seized and secured it and then obtained a warrant to go through the information in the phone. Furthermore, she said, cellphone searches do not typically stem from concern over officer safety or preserving evidence — the two reasons allowed for warrantless searches.
In an interview Tuesday, Matthew Segal, legal director of the ACLU Foundation of Massachusetts, said one reason both liberal and conservative justices voiced concern about privacy interests is because minor arrests could open a person’s cellphone to examination.
“People can get arrested for jaywalking, for failing to wear a seat belt, for all kinds of minor offenses. So if the government wins these cases, the next day, officers all around Massachusetts can just wait for someone to jaywalk and boom, you get to look at their cellphones, which is a window into their entire lives,” Segal said.
The California case heard earlier Tuesday morning stems from a 2009 incident involving a San Diego gang member pulled over for having an expired registration. Upon inspecting his cellphone, police found information that linked him to a murder and he was subsequently sentenced to 15 years to life in prison.
Chief Justice John G. Roberts Jr. questioned the premise that today’s cellphones simply allow police access to the same kinds of information they could have obtained in the past when people carried family photos in their wallets.
“Smartphones carry a lot of information that would not have been the sort of thing police could look at before,” like GPS tracking information that generates a map of everywhere a person had been, Roberts pointed out.
To which Justice Stephen Breyere quipped: “I don’t want to admit it, but my wife might put a little note in my pocket. ‘Stephen, remember, turn right at the third stoplight, proceed three blocks forward.’ ” As long as it was written down, he said, police of yesteryear could have access to a person’s potential whereabouts.
But, Roberts said, a GPS would actually be able to tell if Breyer had, “in fact, turned right at the thing or had gone somewhere else.”
The justices’ questioning also indicated that rather than adopt a categorical rule — that if the phone is in police custody, they were authorized to search it — they could consider narrowing the instances when warrantless searches would be allowed, such as when it relates to the crime for which the suspect is arrested.
The Fourth Amendment dictates that a warrant is typically required from a judge before police can conduct a search.
“The point of a warrant is that a person who is not involved and is objective listens to what the policeman is saying, knowing that sometimes, like me or any other human being, a policeman can get a little carried away,” Breyer said. “You want that third dispassionate mind to review what the facts are.”
The warrant must be based on “probable cause” — or a reasonable suspicion that a crime has been committed — but in the 1970s, the court created exceptions for officers dealing with suspects they have arrested. Several justices questioned how decades-old rules applied to today’s rapidly evolving technology.
“How do we determine what the new expectation of privacy is now?” Justice Samuel Alito asked.
The court is expected to rule on the cases this summer.Material from the Associated Press was used in this report. Tracy Jan can be reached at firstname.lastname@example.org. Follow her on Twitter @GlobeTracyJan.