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The Fourth Amendment in the Digital Age

Summary: The Supreme Court’s Carpenter ruling can shape privacy protections for new technologies.

Published: March 18, 2021
Surveillance of digital devices
Getty/Future Publishing

The Fourth Amend­ment stands for the prin­ciple that the govern­ment gener­ally may not search its people or seize their belong­ings without appro­pri­ate process and over­sight. Today, we are at a juris­pru­den­tial inflec­tion point as courts grapple with when and how the Fourth Amend­ment should apply to the data gener­ated by tech­no­lo­gies like cell phones, smart cars, and wear­able devices. These tech­no­lo­gies — which we rely on for enhanced commu­nic­a­tion, trans­port­a­tion, and enter­tain­ment — create detailed records about our private lives, poten­tially reveal­ing not only where we have been but also our polit­ical view­points, consumer pref­er­ences, people with whom we have inter­ac­ted, and more. The result­ing trove of inform­a­tion is immensely valu­able to law enforce­ment for use in invest­ig­a­tions and prosec­u­tions, and much of it is currently avail­able without a warrant. 

This paper describes how the U.S. Supreme Court’s 2018 decision in Carpenter v. United States has the poten­tial to usher in a new era of Fourth Amend­ment law. In Carpenter, the Court considered how the Fourth Amend­ment applies to loca­tion data gener­ated when cell phones connect to nearby cell towers.  foot­note1_5u29re4 1 Carpenter v. United States, 138 S. Ct. 2206 (2018).  The Court ulti­mately held that when the govern­ment deman­ded seven days of loca­tion inform­a­tion from defend­ant Timothy Carpen­ter’s cell phone provider without a warrant, it viol­ated the Fourth Amend­ment. The decision sits at the inter­sec­tion of two lines of cases: those that exam­ine loca­tion track­ing tech­no­lo­gies, like beep­ers or the Global Posi­tion­ing System (GPS), and those that discuss what expect­a­tion of privacy is reas­on­able for inform­a­tion disclosed to third parties, like banks or phone compan­ies. In reach­ing its conclu­sion that a warrant was required, the Court upen­ded exist­ing preced­ent, ruling for the first time that loca­tion inform­a­tion main­tained by a third party was protec­ted by the Fourth Amend­ment.

In explor­ing the Court’s decision in Carpenter and its applic­a­tion to data from a vari­ety of tech­no­lo­gies — such as GPS, auto­mated license plate read­ers (ALPRs), and wear­ables — this paper argues that it is incum­bent on courts to preserve the balance of power between the people and the govern­ment as enshrined in the Fourth Amend­ment, which was inten­ded to “place obstacles in the way of a too permeat­ing police surveil­lance.”  foot­note2_fbjsyx8 2 Carpenter, 138 S. Ct. at 2214 (quot­ing United States v. Di Re, 332 U.S. 581, 595 (1948)).  Moreover, in determ­in­ing the scope of the Consti­tu­tion’s protec­tions for data gener­ated by digital tech­no­lo­gies, courts should weigh the five factors considered in Carpenter: the intim­acy and compre­hens­ive­ness of the data, the expense of obtain­ing it, the retro­spect­ive window that it offers to law enforce­ment, and whether it was truly shared volun­tar­ily with a third party. Section I is an over­view of Fourth Amend­ment juris­pru­dence. Section II discusses the Carpenter decision and its takeaways. Section III applies Carpenter to vari­ous surveil­lance tech­no­lo­gies and looks ahead at how Fourth Amend­ment juris­pru­dence might continue to develop in the digital age.

End Notes