In a sweeping decision Wednesday, the U.S. Supreme Court said law enforcement officials cannot, in most cases, search personal cellphones unless they first obtain a warrant.
The unanimous ruling is a victory for advocates of digital privacy, but a loss for the Obama administration, which had argued police needed the freedom to search cellphones of people they arrest in order to look for evidence of crimes.
Instead, the court ruled that police who find cellphones on arrestees “must generally secure a warrant” before searching them. A police officer who arrests a suspect may not scroll through that suspect’s phone, looking for recent phone call logs or texts.
The court left an exception for emergency situations, such as when a person’s life is in danger—for example, in the case of a child abductor who might have information about the child’s whereabouts on his phone.
The closely watched case was one that brought questions of personal rights under the Constitution into the age of tablets and smartphones. Although courts had ruled that police may take wallets, weapons, papers, cigarettes, and other items found on a person’s body during an arrest, they were divided on the question of digital information: Cellphone and mobile devices may contain years’ worth of email correspondence, thousands of photos, contact lists, intimate texts, business documents, or GPS location information—much more than can be contained in a wallet or purse.
Chief Justice John Roberts said Wednesday such information is protected by the Fourth Amendment’s right to privacy.
“Allowing a warrantless search of all this information is not just an incidental intrusion,” Roberts said, reading from the court’s decision, which he wrote for the majority. “The fact that technology now allows an individual to carry such information in his hand does not make the information any less worthy of the protection for which the Founders fought. Our answer to the question of what police must do before searching a cell phone seized incident to an arrest is accordingly simple—get a warrant.”
The court issued a single ruling in response to two cases dealing with cellphone searches. In the first, California police searched the smartphone of college student David Riley after arresting him for driving with an expired license plate and suspended license. A gang photo on the phone led to convictions of armed assault and attempted murder, and a California appeals court upheld the search as legal, even though the officers did not have a warrant.
In the second case, police in Boston searched the flip phone of Brima Wurie, arrested for selling crack cocaine. Their search revealed a phone number leading to a house containing drugs and weapons, and resulting in a conviction against Wurie. But a federal appeals court later threw out the evidence gathered from the flip phone, saying the warrantless search was illegal.
Roberts said the court’s reasoning followed that of the authors of the Bill of Rights, who were responding to the colonial era’s experience of British officers, who rummaged through American homes in hopes of finding evidence of criminal activity.
“Opposition to such searches was in fact one of the driving forces behind the Revolution itself,” Roberts said.
The court’s decision noted that the technology ubiquitous in cellphones today was “inconceivable” just a few decades ago. “The sum of an individual’s private life can be reconstructed through a thousand photographs labeled with dates, locations, and descriptions; the same cannot be said of a photograph of two of loved ones tucked into a wallet.”
The court even rejected the assertion that police should be free to search recent call logs, although the justices agreed police should be able to look at a phone to determine whether the device itself poses a threat.
“Law enforcement officers remain free to examine the physical aspects of a phone to ensure that it will not be used as a weapon—say, to determine whether there is a razor blade hidden between the phone and its case,” the court said. “Once an officer has secured a phone and eliminated any potential physical threats, however, data on the phone can endanger no one.”
The court also refuted the Obama administration’s argument that officers needed to search phones immediately in case a criminal had programmed it to be remotely wiped of data in the event of arrest. Such cases were likely to be very rare, the court said. It suggested police could take simple steps to prevent remote wiping, such as turning the phone off or placing it inside a cheap bag that blocks network signals.
“We cannot deny that our decision today will have an impact on the ability of law enforcement to combat crime,” the justices conceded. “Privacy comes at a cost.”