(Bloomberg) — A U.S. Supreme Court with a record of protecting digital privacy is taking up a case that may curb law enforcement officials’ power to track people using mobile-phone data.
In arguments Nov. 29, the justices will consider requiring prosecutors to get a warrant before obtaining mobile-phone tower records that show a person’s location over the course of weeks or months.
The case could have a far-reaching impact. Prosecutors seek phone-location information from telecommunications companies in tens of thousands of cases a year. Special Counsel Robert Mueller’s team used location data to build a case against George Papadopoulos, the former Trump campaign adviser who pleaded guilty to lying to federal investigators.
Beyond location data, the case has implications for the growing number of personal and household devices that connect to the cloud — including virtual assistants, smart thermostats and fitness trackers.
“The data that is transmitted can reveal a wealth of detail about people’s personal lives,” according to a court filing by technology companies including Apple Inc., Facebook Inc., Microsoft Corp., Verizon Communications Inc., Twitter Inc. and Google Inc. “Users of digital technologies reasonably expect to retain significant privacy in that data.”
The high court case involves Timothy Ivory Carpenter, who is seeking to overturn his conviction for taking part in a string of armed robberies of Detroit-area Radio Shacks and, ironically, stores for wireless provider T-Mobile US Inc.
At trial, prosecutors used four months of data obtained from Carpenter’s wireless carriers to show he was within a half-mile to two miles of the location of four of the robberies when they occurred. Mobile-phone companies typically keep records that show the cell sites where their customers’ calls begin and end.
Prosecutors in most of the country can get that data without a warrant through the 1986 Stored Communications Act. That law says prosecutors need only have “reasonable grounds” to believe the information would be useful in an investigation. A court warrant would require a stronger showing of “probable cause.”
A federal appeals court upheld Carpenter’s conviction, rejecting his argument that the Constitution’s Fourth Amendment required prosecutors to get a warrant. The Fourth Amendment bars unreasonable searches.
The Trump administration says the appeals court got it right, pointing to a 1979 Supreme Court decision involving the phone numbers a person dials. The court said those numbers aren’t constitutionally protected because the caller has already provided them to a third party — that is, the phone company.
“This court has long held that an individual cannot invoke the Fourth Amendment to object to the government’s acquisition of a third party’s records that contain information about the individual,” U.S. Solicitor General Noel Francisco argued in court papers.
Carpenter says that reasoning shouldn’t apply to digital privacy given the vast amounts of data at stake — 186 pages of location records in his case. That information is “orders of magnitude more granular and revealing” than the dialed numbers at issue in the 1979 case, Carpenter’s lawyers said.
His allies say the privacy dangers are still growing. Newer technology allows phones to be pinpointed to within 50 meters, privacy advocates led by the Electronic Frontier Foundation argue in court papers.
Wary of Technology
The Supreme Court under Chief Justice John Roberts has shown itself to be wary of technology and its privacy implications. In 2012, the high court put limits on the power of police to attach tracking devices to cars.
Two years later, the court said the Fourth Amendment generally requires police to get a warrant before searching the phone of someone who is being arrested. Writing for the court, Roberts pointed to the trove of information carried by modern phones.
“It is no exaggeration to say that many of the more than 90 percent of American adults who own a cell phone keep on their person a digital record of nearly every aspect of their lives — from the mundane to the intimate,” Roberts wrote.
Although both rulings were unanimous, they revealed fault lines that could prove important in the Carpenter case. Writing separately in the 2014 case, Justice Samuel Alito said he might defer to Congress if it enacted legislation that balanced privacy interests with law enforcement needs.
Responding to Changes
“Legislatures, elected by the people, are in a better position than we are to assess and respond to the changes that have already occurred and those that almost certainly will take place in the future,” Alito wrote.
A key question in the Carpenter case is how much deference the court should give the Stored Communications Act, a measure enacted more than two decades before the first iPhone was sold.
A ruling that holds government officials to a higher standard could be especially important in cases involving narcotics and firearms. Those prosecutions commonly rely on location data, said Hanley Chew, a former federal prosecutor who now represents technology companies at the law firm Fenwick & West.
“It’s going to require law enforcement to do more investigating before they go to court for cell-site information,” Chew said. “As a result of that, it might slow down some investigations.”
The court will rule by June in the case, Carpenter v. United States, 16-402.