Carpenter v. United States: A New Era for Protecting Data Generated on Personal Technology, or a Mere Caveat?

In deciding Carpenter, a majority of United States Supreme Court Justices recognized that, at a fundamental level, historical cell-site location information (CSLI) differs from other categories of business records in terms of deserving Fourth Amendment protection. However, the majority’s opinion is unclear about the precise source of this distinction, and about how, or whether, to protect other data generated from personal technology in the future. Although the majority opinion purports to be limited to CSLI, this narrow scope is not in the best interest of consumers. At best, Carpenter presents the opportunity to establish a predictable and comprehensive system for protecting personal data from warrantless search. However, the majority’s approach also risks becoming a mere caveat, drawing artificial distinctions between CSLI and other types of data that may be equally, or more, sensitive. Now that the Supreme Court has recognized some forms of data held by businesses are protected from warrantless search, this holding should be expanded to protect the increasingly comprehensive consumer data that companies acquire. Although Justice Kennedy’s dissent in Carpenter highlighted the risks of the majority’s unstructured approach, Justice Sotomayor’s concurrence in United States v. Jones provided an aspirational glimpse of how personal data could be protected in the future. Courts should read Carpenter in conjunction with Justice Sotomayor’s Jones concurrence to provide a predictable standard for evaluating personal data protections and avoid the uncertain approach that the Carpenter majority’s opinion risks establishing