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Supreme Court Ruling on Location Data Leaves Open Key Questions

In a long-anticipated decision, the United States Supreme Court ruled the Fourth Amendment protects location information collected by cellular service providers and that law enforcement must first obtain a warrant. The decision was a narrow one, as the Court left open the question whether other kinds of digital information such as Internet browsing history and third-party data collection could fall under Fourth Amendment protections.

“When the Government tracks the location of a cell phone it achieves near perfect surveillance, as if it had attached an ankle monitor to the phone’s user,” Chief Justice John Roberts wrote in the majority opinion for Carpenter v United States, noting that it lets the government “travel back in time to retrace a person’s whereabouts.”

“Just because you have to trust a third party with your data doesn’t necessarily mean you should lose all Fourth Amendment protections in it,” Chief Justice Roberts wrote.

Law enforcement increasingly rely on cell phone records to look at people’s movements to evaluate leads, verify tips from informants, verify victim whereabouts, and corroborate witness accounts. In 2016, AT&T received more than 70,000 requests, and Verizon received 53,000 requests, according to a brief submitted by the Electronic Frontier Foundation to the Supreme Court arguing for Fourth Amendment protections.

The case centered around Timothy Carpenter, who was arrested in 2011 for a string of robberies against Radio Shack and T-Mobile stores. He was convicted after FBI agents used cell phone location records from MetroPCS and Sprint to show he was present at those locations during the robberies. Carpenter argued that the fact that FBI agents were able to get 12,898 location points out of 127 days of historic data, such as when he slept at home and which Sundays he went to church, without a search warrant was an overreach and beyond the narrow confines of an investigation.

What’s needed is an approach more nuanced than a “mechanical interpretation of the Fourth Amendment.”

The question for the Supreme Court wasn’t whether law enforcement could use cell phone location records in its investigations, but rather how it could obtain the information. Under the Stored Communications Act, law enforcement just needs to show “specific and articulable facts showing that there are reasonable grounds to believe” that the requested tracking data is “relevant and material to an ongoing criminal investigation.”

Under the legal principle of third-party doctrine, information customers voluntarily provide to a third-party, such as a telecommunications company (Smith v Maryland, 1979) or a bank (United States v Miller, 1976), does not fall under the purview of the Fourth Amendment because the customer had already revealed that information to that entity. The Carpenter decision said the doctrine did not apply to cell phone records, because technology has progressed to the point where tracking is ubiquitous.

“Whoever the suspect turns out to be, he has effectively been tailed every moment of every day for five years, and the police may—in the Government’s view—call upon the results of that surveillance without regard to the constraints of the Fourth Amendment. Only the few without cell phones could escape this tireless and absolute surveillance,” the court wrote in the ruling.

The time-stamped cell phone records provide “an intimate window into a person's life,” revealing not only his or her particular movements, but also "familial, political, professional, religious, and sexual associations,” Chief Justice Roberts wrote. “Critically, because location information is continually logged for all of the 400 million devices in the United States—not just those belonging to persons who might happen to come under investigation—this newfound tracking capacity runs against everyone.”

An interesting part of this decision was the fact that the Court’s opinion “presents the technology as vastly more invasive and detailed than the record indicates,” University of Southern California Gould School of Law professor Orin Kerr wrote on the Lawfare blog. In Carpenter, the cell phone records were precise to a range of 0.5 to 2 miles and were generated only if someone made a call.

“The technology isn't actually perfect and absolute surveillance now, but the Justices are confident that it is going to be that eventually,” Kerr wrote.

Just because you have to trust a third party with your data doesn’t necessarily mean you should lose all Fourth Amendment protections in it.

“Justice Roberts appears to have written a sweeping 21st century opinion on the Fourth Amendment: recognizing the profound changes wrought by technology and the resulting need to create new protections for ordinary people,” wrote Elizabeth Joh, constitutional law professor at University of California, Davis School of Law.

Companies currently hold a lot of data about individuals, thanks to the growing use of cloud services, increased technology capabilities, and rampant data collection. Users are concerned about what information is being collected and who has access to it, and government wants tech companies to stop putting in security features that make it harder to get at the data. The development of technology has required the Supreme Court to find ways to preserve privacy from the government even when surveillance tools have enhanced the government's ability to “encroach on areas normally guarded from inquisitive eyes,” Chief Justice Roberts wrote.

What’s needed is an approach more nuanced than a “mechanical interpretation of the Fourth Amendment.”

Not a definitive ruling

Under the ruling, law enforcement has to first get a search warrant for historic cell phone location data by convincing a judge the information is important and relevant to the investigation. While the warrant requires a bigger burden of proof than just getting a subpoena, it isn’t a very high barrier. Investigators and prosecutors just have to find someone willing to accept their arguments, and some judges are willing to give a lot of leeway in these cases.

While there is a lot of language in the opinion to suggest that the ruling can apply to emails and text messages, browsing history, and other types of data collected for advertising purposes, this case doesn’t presume to weigh in on those areas. It isn’t clear just how the ruling would be applied in practice, especially since law enforcement could still obtain location information without a warrant in emergencies, such as “bomb threats, active shootings, and child abductions.” The majority opinion also left unanswered the question of whether a warrant is necessary if the requested time period is fewer than seven days—the time period requested from Sprint in the Carpenter case.

The majority opinion is a very narrow one as it applies to only cell phone location data, and Chief Justice Roberts said he didn’t want to make sweeping generalizations when technology was changing so quickly. Despite Justice Sonia Sotomayer’s urgings to revisit the third party doctrine in light of 21st century technology during oral arguments, the decision completely sidesteps that minefield. In fact, Justice Neil Gorsuch seemed to suggest in his dissent that the majority didn’t go far enough, considering how much information currently reside on third-party servers.

“Can the government demand a copy of all your e-mails from Google or Microsoft without implicating your Fourth Amendment rights? Can it secure your DNA from 23andMe without a warrant or probable cause? Smith and Miller say yes it can...But that result strikes most lawyers and judges today—me included—as pretty unlikely,” Gorsuch wrote in his dissent.

Justice Samuel Alito wrote in his dissent that the majority ruling would expose the Court to the “embarrassment of explaining in case after case” that there were “all sorts of qualifications and limitations that have not yet been discovered. We will be making repairs—or picking up the pieces—for a long time to come,” Alito wrote.