Obtaining Cell Site Location Information Is a Fourth Amendment Search

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Carpenter v. United States, S.Ct. (2018)

The Supreme Court ruled last week in favor of Timothy Carpenter, convicted in a string of armed robberies of RadioShack and T-Mobile stores. In a 5-4 split decision, the majority opinion was written by Chief Justice John Roberts. He was joined by the Court’s four more liberal justices. In a rare move—it has only happened with Chief Justice Roberts once before—each of the conservative dissenting justices wrote individual opinions sharply disagreeing with the majority on several points.

The prosecution obtained Carpenter’s cell site location information (CSLI) with an order issued under the Stored Communications Act, which allows access to CSLI if the prosecution has reasonable grounds to believe the CSLI will help a criminal investigation. I laid out the facts in Carpenter’s case in this article in an earlier issue of Xiphos.

The Court held that providing more than seven days of CSLI violated Carpenter’s “legitimate expectation of privacy in the record of his physical movements.” The Court termed the CSLI as “deeply revealing.” That’s an unfair stretch. The technological data provided by Carpenter’s mobile phone service provider revealed his location with accuracy as vague as a range of two miles. While his CSLI might have placed him at a liquor store or adult book store, it might just as likely suggested he was in a prayer meeting at the evangelical storefront church five blocks away. Chief Justice Roberts’ opinion suggests a far more precise tracking ability than the technology delivers.

Chief Justice Roberts also asserted that the majority ruling is narrow, a claim sharply contested by Justices Kennedy and Alito. “We do not begin to claim all the answers today,” the Chief Justice wrote, “and therefore decide no more than the case before us.” Attempting to delineate the limitation on the third-party rule (generally a person has no expectation of privacy in records voluntarily shared with a third party), Chief Justice observed that the third-party doctrine will apply in the “overwhelming majority of investigations” and it will be “the rare case where the suspect has a legitimate privacy interest in records held by a third party.”

Just how far the majority impinges on the third-party doctrine doesn’t seem to be as clear and as harmless as Justice Roberts suggests. The majority opinion states the request for Carpenter’s CSLI wasn’t a “garden-variety request for information from a third party.” The roots of the third-party doctrine are in requests for “limited types of personal information,” the majority noted, such as bank records and lists of numbers dialed from a telephone. CSLI is different: “Seismic shifts in digital technology … made possible the tracking of not only Carpenter’s location but also everyone else’s, not for a short period but for years and years.”

Chief Justice Roberts, perhaps in a nod to scores of teenagers with eyes focused on screens or freeway drivers with thumbs on the keypads, observed that a mobile phone is “almost a feature of human anatomy” and that carrying a mobile phone “is indispensable to participation in modern society.” Thus, sharing location information with the mobile phone service provider isn’t really a voluntary choice. Whether the need for constant text messaging and keeping up with the latest Kardashian relationship is truly “indispensable,” it still seems to be a choice to carry a phone. Recognizing this, Justice Gorsuch criticized the majority for placing the third-party doctrine on “life support.”

What’s the bottom line for investigators? The core rule of Carpenter v. United States is that accessing historical CSLI of at least seven days or more is a “search” under the Fourth Amendment and requires a warrant based upon probable cause. The Court held, “We need not decide whether there is a limited period for which the Government may obtain an individual’s historical CSLI free from Fourth Amendment scrutiny, and if so, how long that period might be. It is sufficient for our purposes today to hold that accessing seven days of CSLI constitutes a Fourth Amendment search.” That leaves open the possibility of obtaining CSLI for the specific date on which a crime was committed may not require a warrant. And the ruling left room for warrantless access to CSLI in an emergency, such as “bomb threats, active shootings, and child abductions.”

The Carpenter decision is about identifying a person’s movements through historical CSLI. But the opinions are chock full of hints of current disagreements and future debates over how the Fourth Amendment applies to emerging technology. Justice Alito criticized the majority’s analysis as “revolutionary” and said the majority rule threatened investigations into terrorism and political corruption. Justice Gorsuch’s opinion argues for analysis focusing on whether Carpenter had a property interest in the CSLI records, an issue not touched by the lower courts. If Carpenter’s lawyers had argued for treatment of his CSLI as “papers,” there is every sign that Justice Gorsuch would have extended Fourth Amendment protection to them. Justice Kennedy wrote that this case should have been resolved by straightforward application of the third-party doctrine precedent. No matter what Chief Justice Roberts claims, the majority opinion clearly hacks away at the third-party doctrine.

Final observation: Having just spent a few thousand miles with a Harley-Davidson mobile therapy machine and mostly without a working mobile phone, I urge the justices (and all of us) to get out more.

Ken Wallentine

KEN WALLENTINE is the Chief of the West Jordan (Utah) Police Department and former Chief of Law Enforcement for the Utah Attorney General. He has served over three decades in public safety, is a legal expert and editor of Xiphos, a monthly national criminal procedure newsletter. He is a member of the Board of Directors of the Institute for the Prevention of In-Custody Death and serves as a use of force consultant in state and federal criminal and civil litigation across the nation.

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