WASHINGTON – A deeply divided Supreme Court once again defended digital privacy rights Friday in a decision with implications for anyone who carries a cellphone.
The justices ruled 5-4 that police need a warrant to access data from mobile service providers that shows where an individual has traveled over weeks, months or even years.
The opinion by Chief Justice John Roberts, who was joined by the court's four liberal justices, follows a long line of cases in which the court has reinterpreted the constitutional right to privacy for the digital age. Most recently, the justices ruled that police cannot use GPS equipment to track vehicles or search cellphones without a warrant.
But unlike those unanimous rulings, Friday's came with four vociferous dissents from the court's other four conservative justices that ran for 92 pages. Three of them warned that the decision would tie the hands of police investigating violent crimes. Justice Neil Gorsuch aligned himself with privacy rights but under a different theory.
The case grew out of a series of armed robberies in Michigan and Ohio in 2010 and 2011. To prosecute its case against Timothy Carpenter, the government obtained cellphone records that revealed his approximate location over 127 days, placing him in proximity to four of the crimes.
The records were obtained under the Stored Communications Act of 1986, which allows phone companies to turn over records if the government has reasonable grounds to believe they will help a criminal investigation.
In 2016, police made some 125,000 requests for data from Verizon and AT&T alone. Courts routinely grant those requests. Nine states, including California, already require a search warrant, which is harder for police to get.
Lower courts upheld the search of cell tower records under the "third-party doctrine," used in earlier Supreme Court cases to uphold government access to suspects' bank records, as well as phone numbers called from landlines. Consumers should know that wireless carriers can track them, the theory goes, so their locations are not private.
'Everyone' is at risk
But the court ruled that cellphone location data is different. When the court decided two cases in the 1970s under the third-party doctrine, Roberts said, "few could have imagined a society in which a phone goes wherever its owner goes, conveying to the wireless carrier not just dialed digits, but a detailed and comprehensive record of the person’s movements."
Furthermore, he said, the threat to privacy extends beyond criminal suspects to the 400 million devices in the United States. "This newfound tracking capacity runs against everyone," Roberts warned.
"While individuals regularly leave their vehicles, they compulsively carry cell phones with them all the time," he said. "A cell phone faithfully follows its owner beyond public thoroughfares and into private residences, doctor’s offices, political headquarters, and other potentially revealing locales."
The chief justice stressed that the ruling was along narrow grounds. He said conventional surveillance techniques and tools, such as security cameras or even monitoring cellphone location data in real time, remain constitutional. And he said warrants can be skipped in extreme cases involving imminent threats.
As is seldom the case, Roberts was alone among the court's conservatives. Justice Anthony Kennedy said the government's search of cellphone location records was permissible because they were held by the service provider, not the individual, and helped police crack a string of burglaries.
"The new rule the court seems to formulate puts needed, reasonable, accepted, lawful, and congressionally authorized criminal investigations at serious risk in serious cases, often when law enforcement seeks to prevent the threat of violent crimes," he said.
Justice Samuel Alito went further, calling it a "revolutionary" ruling that could stymie investigations of terrorism, political corruption, white-collar crime and other offenses. He said it "guarantees a blizzard of litigation while threatening many legitimate and valuable investigative practices."
Unlike the other dissenters, however, Gorsuch indicated he would have ruled in favor of privacy rights had a different argument been raised -- that the location records remain the individual's property even while held by a mobile service provider.
"It seems to me entirely possible a person’s cell-site data could qualify as his papers or effects under existing law," he said.
Seeing through walls
As the case was being argued, privacy groups warned that extending the third-party doctrine to cellphone location data could be a slippery slope leading to exposure of email and text messages, social media communications, Internet browsing histories and the so-called "Internet of Things," from Siri to Fitbits.
"Today’s decision rightly recognizes the need to protect the highly sensitive location data from our cell phones, but it also provides a path forward for safeguarding other sensitive digital information in future cases — from our emails, smart home appliances, and technology that is yet to be invented,” said American Civil Liberties Union attorney Nathan Wessler, who argued Carpenter's case at the court in November.
Major technology companies had submitted briefs on Carpenter's side, including Google, Facebook, Apple, Verizon, Twitter, Cisco and Microsoft. They urged the court to reconcile Fourth Amendment protections with "the changing realities of the digital era."
Since 2001, the court has leaned toward protecting privacy from modern technology. That year, it ruled 5-4 that police needed a search warrant to use a thermal imaging device outside a private home to detect the heat required to grow marijuana inside. The GPS and cellphone contents rulings followed in 2012 and 2014.
Roberts referred to the thermal imaging case a decade later in identifying the clash between privacy and technology as "the real challenge for the next 50 years."
"What does the Fourth Amendment mean when you can, through technology, literally see through walls with heat imaging?" he said.