Top court adopts new rules for cell tracking

Washington — In a decision arising from a Detroit case, the U.S. Supreme Court ruled Friday that the government generally needs to obtain a search warrant to access a cellphone owner’s location history.

The case involves Detroit robber Timothy Ivory Carpenter, 33, who had objected to prosecutors using his cellphone records, arguing that the government never got a warrant for the information based on probable cause.

Privacy advocates hailed the justices’ 5-4 decision as one of the most important decisions of the court’s term and a significant win for privacy protections in the digital era.

The result will have consequences for how law enforcement may access cellphone records from wireless carriers.

A warrant will generally be required before authorities may obtain the digital data collected by cellphone companies tracking a person’s location and movements over a period.

The court stopped short of spelling out a principle of law for all digital surveillance cases, but a majority of the justices said Friday that the government’s acquisition of 127 days worth of Carpenter’s cell-site records constituted a Fourth Amendment search.

Chief Justice John Roberts, who authored the majority opinion, called the ruling a “narrow” one, as a warrant is required “only in the rare case where the suspect has a legitimate privacy interest in records held by a third party.”

Roberts said the court’s decision is limited to cell-tracking data and explicitly does not apply to what are known as “tower dumps” — the downloading of data from a particular cell tower of all devices that connected the tower during a specific time period.

The American Civil Liberties Union, who helped represent Carpenter, called the ruling a “groundbreaking victory” for privacy rights in the digital age.

ACLU attorney Nathan Freed Wessler, who argued the case before the court, also suggested it provides a “path forward” for safeguarding other personal digital information in future cases, such as emails, smart home appliances and “technology that is yet to be invented.”

Roberts clarified that law enforcement may still obtain records without a warrant under exigent circumstances, such as bomb threats, active shootings and kidnappings.

Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor and Elena Kagan joined Roberts’ opinion, which reversed and remanded the case to the U.S. Court of Appeals for the 6th Circuit.

Justices Anthony Kennedy, Samuel Alito, Clarence Thomas and Neil Gorsuch each dissented separately.

Kennedy raised concerns about the ruling’s effect on other tools that investigators use to collect evidence. He wrote that the court’s “new and uncharted course will inhibit law enforcement and ‘keep defendants and judges guessing for years to come.’ ”

Carpenter’s attorney, Harold Gurewitz of Detroit, said the ruling will open to challenge similar cases in which police obtained cellphone location records using a court order with a lower standard than the “probable cause” needed for a warrant.

In a footnote, Roberts said a warrant would be needed to access at least seven or more days of cellphone location data. In Carpenter’s case, the cellphone data collected covered 127 days.

“The court, I think, really had no problem saying tracking someone for that period of time retroactively — going back and looking at records showing every place a person’s cellphone has been for three or four months — is an invasion of what everyone commonly expects is private,” Gurewitz said.

“Almost everybody in the country has a cellphone, and cellphones automatically create these kinds of records. And that is the problem — which is defined by technology.”

Carpenter, 33, was convicted and sentenced to more than 116 years in federal prison in 2014 for his role in a series of armed robberies at RadioShack and T-Mobile stores in Michigan and Ohio.

Investigators obtained the 127 days’ worth of data from cell towers about the location of Carpenter’s cellphone, which FBI agents retroactively used to place Carpenter near the scene of the crimes around the times that the robberies occurred.

The lower courts and the government said the case was covered by the “third-party doctrine,” which holds that the Fourth Amendment does not protect records or information that is shared with a third party, such as a cellphone phone company.

The High Court disagreed, highlighting the “unique nature” of cellphone location data and finding the fact that the government obtained it from a third party “does not overcome Carpenter’s claim to Fourth Amendment protection,” Roberts wrote.

The government had relied in part on a 39-year-old decision, Smith v. Maryland, from the High Court that treats phone records differently than a phone conversation, for which a warrant generally is required.

Roberts noted that Smith arose in the pre-digital age — before people began carrying phones with them everywhere and, in so doing, conveying a detailed, continuous record of their whereabouts to their wireless company.

“When the government tracks the location of a cellphone, it achieves near-perfect surveillance, as if it had attached an ankle monitor to the phone’s user,” Roberts wrote.

H.V. Jagadish, a professor of electrical engineering and computer science at the University of Michigan, was “delighted” that the justices understood the qualitative changes that technology can bring about, he said.

“For a long time, the ‘third-party doctrine’ has held that a person cannot reasonably expect to keep private any information voluntarily conveyed to a third party,” said Jagadish of the Michigan Institute for Data Science.

“While this may be appropriate for a ‘secret’ you tell a ‘friend,’ it should not apply to the information given to service providers.”

Harry Sandick, a former federal prosecutor in New York, said the court recognized something is “qualitatively different” when the government monitors a cell-site location for 127 days than when it uses human surveillance or obtains bank records.

“The court was confronted with rather extreme facts here. There were literally 12,898 data points, an average of 101 data points a day,” said Sandick, who filed an amicus brief with the court on behalf of 42 scholars of criminal procedure and privacy law.

“This is different from a case where there was a kidnapper, and we needed to find him, and we got the cell site data for a day and saved a person’s life. That’s still permitted.”

It’s important the court balance the ability of law enforcement to take advantage of new technology with people’s “understandable desire to still have some shield of privacy,” he added.

“If the decision had come out the other way, the court would have essentially said by virtue of carrying a cellphone, you consent to round-the-clock monitoring and the government can get access to that data any time it wants without making any particular showing at all,” Sandick said.

“And Chief Justice Roberts and the justices in the majority were not comfortable with that world.”

mburke@detroitnews.com