The Supreme Court raised concerns Tuesday about whether police have the constitutional right to search the cellphones of people they arrest.
The justices addressed the privacy rights issue during oral arguments in a pair of cases in which defendants were convicted and sentenced to prison partly because police obtained key evidence from their cellphones after a warrantless search.
Justice Elena Kagan worried that those searches violate privacy rights because "people carry their entire lives in their cellphones."
"A person can be arrested for driving without a seat belt and the police could take that phone and look at every single email that person has written, including work emails, including emails to family members — very intimate communications," she said.
Justice Ruth Bader Ginsburg said she doesn't understand "why we've cut the warrant out of the picture."
The Fourth Amendment says that police generally need a warrant before they can conduct a search and that the warrant must be based on "probable cause" evidence that a crime has been committed.
But the Supreme Court has made exceptions when people are arrested, saying that police don't need a warrant to search the belongings a suspect is carrying at the time of his or her arrest.
Police, as well as the Justice Department, have argued that searches are vital to ensure evidence isn't tampered with or destroyed.
But privacy advocates and defense lawyers say that because cellphones potentially contain vast amounts of personal information unrelated to a person's arrest, they should be off limits to a police search without a warrant.
Attorneys for the police and federal government told the justices that police are interested only in evidence pertinent to a person's arrest and aren't interested in gleaning personal information from cellphones.
"You can just rove through the phone. You need to keep a scope focus," said Deputy Solicitor General Michael Dreeben.
But some justices suggested it's unrealistic for police to immediately know what information is relevant and what isn't — particularly in the heat of making an arrest.
Justice Stephen Breyer said it's not unreasonable to suggest that police could accidentally collect too much information from a person's cellphone in the heat of an arrest.
"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 police can get a little carried away," he said.
The government also argued that searches of cellphones pose little legal difference than when police search the contents of a person's wallet at the time of an arrest, which they already have the authority to do.
But Justice Anthony Kennedy suggested that cellphones pose different privacy challenges than wallets.
"I don't think it odd to say we are living in a new world," he said.
In one of two cases, a California state court upheld the conviction of David Leon Riley after San Diego police found evidence on his smartphone that he belonged to a gang and was involved in a gang-related shooting. Prosecutors used video and photographs found on the smartphone to persuade a jury to convict Riley of attempted murder and other charges.
In the other case, from Boston, a federal appeals court said the warrantless search of a cellphone belonging to Brima Wurie violated the Fourth Amendment. After arresting him on suspicion of selling crack cocaine, police examined the call log on his older model "flip phone" and used the information to determine where he lived. When they searched his home after obtaining a warrant, they found crack, marijuana, a gun and ammunition.
Attorneys for California and the federal government added that because many smartphones have encryption features, it's imperative police have immediate access to the devices before they are disabled or locked — either by the owner or by someone remotely.
The justices appeared somewhat less concerned over warrantless searches of older cellphones, which aren't connected to the Internet.
Justice Antonin Scalia said that "our rule [of law] is, if you're arrested, police can seize it and examine it."