Carpenter v. United States: Cell Phone Location Data Requires Warrant

In late June, the United States Supreme Court issued its ruling in Carpenter v. United States, 585 U.S. ____, No. 16-402 (June 22, 2018), a closely watched criminal case addressing whether law enforcement officials can secure cell-site location information without a warrant issued on probable cause. Writing for the Court, Chief Justice Roberts opined that acquisition of historical cell-site location records is a Fourth Amendment search and therefore requires a warrant. While the holding is ostensibly a victory for privacy advocates, the tension between the five-justice majority opinion and the views of the four dissenting Justices signals a potential future shift in the Court’s privacy analyses.

Carpenter was convicted of robbery after prosecutors presented data from cell phone towers tracking his movements and putting him in the vicinity of several robberies when they occurred. The government had obtained the cell site location information by court order under the Stored Communications Act, which requires a showing of specific facts that there are “reasonable grounds to believe” the records sought will aid an ongoing criminal investigation. Carpenter argued that the data collection constituted a search under the Fourth Amendment and required a criminal warrant supported by the higher “probable cause” standard.

The Fourth Amendment protects the “right of people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures.” Under Supreme Court precedent, Katz v. United States, 389 U.S. 347 (1967), the Fourth Amendment, however, protects “people not places.” Under Katz, a Fourth Amendment search occurs when a person seeks to preserve something as private and his expectation of privacy is one that society recognizes as reasonable. The Court opined that Carpenter’s cell location data sits at the intersection of two lines of authority under this broad rubric. The first recognizes a reasonable expectation of privacy in a person’s physical location and movements. The second holds that a person loses privacy protections when he voluntarily gives information to a third-party.

Recognizing the pervasive and virtually involuntary intrusion of cell phone technology into every aspect of modern human life, the Court found that privacy considerations override any perceived privacy loss due to third party involvement. In this narrow context, “[i]n light of the deeply revealing nature of [the data], its depth, breadth and comprehensive reach, and the inescapable and automatic nature of its collection, the fact that such information is gathered by a third party does not make it any less deserving of Fourth Amendment protection.” Carpenter, slip op. 22.

Justices Ginsburg, Breyer, Sotomayor, and Kagan joined the opinion of the Court. Just as interesting and perhaps more telling for the future of privacy jurisprudence were the arguments by the multiple dissenting opinions. Justice Kennedy focused primarily on the fact that the records at issue were exclusively within the possession, custody, or control of a third party, not the defendant claiming that his reasonable expectation of privacy had been violated. Justice Kennedy also emphasized the importance of the property-based underpinnings of the Fourth Amendment. Finally, Justice Kennedy raised concern about the workability of the Court’s standard, as well as the wisdom of judicially interfering with an applicable standard already created by the legislature (the Stored Communications Act).

Justice Thomas centered his attack on Katz as precedent, which he argued is untethered from and unsupported by the text of the Fourth Amendment. According to Justice Thomas, the focus of Fourth Amendment jurisprudence should be property rights, not privacy rights. Writing that the Court’s decision “fractures two fundamental pillars of Fourth Amendment law,” Justice Alito argued that the Court improperly conflated an actual search with a court order for document production. Sip op. 1 (Alito, J. dissenting). He also found it “revolutionary” to extend an individual’s Fourth Amendment search rights to a third party’s property.  Id.

Justice Gorsuch also argued for a return to the property-based roots of the Fourth Amendment. He argued that the established property concept of bailment helps overcome the difficult questions posed by increasingly personal individual data held by third parties. In conjunction, he urged the Court to revisit the Fifth Amendment and query whether its protections against self-incrimination might also serve to address problems raised by new technologies. He also left open the possibility, despite dissenting from the decision based on the record before him, that “[i]t seems entirely possible a person’s cell-site data [in the possession of a third party] could qualify as his papers or effects under existing law.” Slip op. 20 (Gorsuch, J. dissenting).

In short, while the Carpenter decision stands as precedent in favor of individual privacy rights, it is clear that the line of authority and analysis on which it is based is not without its significant critics. Given that thorny privacy issues are emerging every day in the context of big data, the issue will inevitably be before the Court again, and a new framework for analysis may ultimately emerge.