The Carpenter Chronicle: A Near Perfect Surveillance

Abstract

For well over a quarter century, law enforcement has surreptitiously converted the personal cell phone into a tracking device, capable of compiling a comprehensive chronicle of the user’s movements over an extended period of time. With the 2018 Carpenter v. United States decision the Supreme Court has confronted the constitutionality of this practice and determined that a warrant based on probable cause is required by the Fourth Amendment. In doing so, the Carpenter Court adopted a normative approach well suited for the question presented but long avoided by lower courts. It also significantly circumscribed the “third party doctrine”; this new limitation will no doubt reverberate throughout many decisions involving nonpublic databases that hold vast and ever-growing amounts of our digital data.

Scholars debate whether the legislative or the judicial branch is better equipped to adjust the balance between security and privacy as new tools become available. In the case of cell phone tracking, both branches were slow and neither was effective, permitting millions of searches that have now been declared unconstitutional. One lesson of Carpenter is that courts must not be reluctant to confront the challenges of twenty- first-century technology. Another is that Congress and state legislatures need to design a better system for ensuring that law enforcement is subject to public accountability before using these powerful new surveillance tools.

In addition to relating the history leading up to Carpenter, this article dissects the decision and, in the process, lays out the multi-factor analysis applied by the Court. It also demonstrates how the Court limited the traditionally applied third party doctrine as it relates to cell phone data. Finally, the authors project the possible impact of the Carpenter decision in an increasingly complex telecommunications arena.

Keywords: Carpenter v. United States, cell phone records, privacy, Fourth Amendment, third party doctrine