SCOTUS: Warrant generally needed to track cell phone location data
01:41 - Source: CNN

Editor’s Note: Jeffrey Toobin is CNN’s chief legal analyst and an author, most recently, of “American Heiress: The Wild Saga of the Kidnapping, Crimes and Trial of Patty Hearst,” and “The Oath: The Obama White House and the Supreme Court.” Follow him on Twitter @JeffreyToobin. The opinions expressed in this commentary are solely those of the author.

CNN  — 

James Madison never had a cell phone – not even a flip phone! But the Supreme Court is frequently called on to conjure what Madison and the other framers of the Constitution might have made of our world, one very different from the one they knew.

On Friday, a deeply divided court considered whether the police could track the location of a cell phone, and thus the person who uses it, without first obtaining a search warrant. Chief Justice John Roberts wrote, “The question we confront today is how to apply the Fourth Amendment to a new phenomenon: the ability to chronicle a person’s past movements through the record of his cell phone signals.”

The case had a straightforward origin. In 2011, the police in Detroit learned of a group of men who were robbing (irony alert) T-Mobile stores, among other places. The police knew the phone numbers of some of the suspects, and they used cell tower information to track their movements. They arrested Timothy Carpenter, who was convicted of multiple counts related to the robberies and sentenced to more than a hundred years in prison.

He challenged the evidence in his appeal, and the court in Carpenter v. United States, by a vote of 5-4, overturned his conviction on the ground that the police had not first obtained a search warrant for the cell data. (Carpenter will likely face a new trial.)

The central issue in the case, according to the court’s precedents, was a deceptively simple one: did the defendant have a “reasonable expectation of privacy” in the cell phone data obtained by the police? Do cell phone users – that is, pretty much everyone – have a reasonable belief that the police will not track their movements through their phones? At one extreme, it’s clear that we expect the police will not listen to our phone calls without a warrant.

At the other extreme, we expect the phone company will bill us for our calls and thus know the numbers we call. But what about the issue in the Carpenter case? This is where the justices split.

Roberts plus the court’s four liberals – Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor and Elena Kagan – said Carpenter did have a reasonable expectation that the police would not track him. The four conservatives – Anthony Kennedy, Clarence Thomas, Samuel Alito and Neil Gorsuch – said Carpenter should have no such expectation; thus, in their view, the police did not need a warrant in his case.

Roberts based his opinion, in part, on the obsessive nature of Americans’ relationships with their phones. “A cell phone faithfully follows its owner beyond public thoroughfares and into private residences, doctor’s offices, political headquarters, and other potentially revealing locales,” he wrote, even noting one survey (which was news to me) that 12% of people admitted that they even use their cell phones in the shower.

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    It was only fair, Roberts concluded, to demand that the police seek a warrant before delving into this nearly sacrosanct private relation between human and phone.

    Still, the basis for the court’s decision shows how tenuous the conclusions should be in this area of the law. What’s reasonable? That depends on how we – and the court – perceive our relationship to technology. And that technology, of course, is constantly changing. It’s easy to criticize the court (and I frequently do it with enthusiasm), but cases like this one show the difficulty of applying Mr. Madison’s Constitution in the modern world.

    Even with the best intentions, and the clearest facts, it’s not obvious what Madison and the other framers would want their heirs to do.