Lawfare: The Impact of Carpenter v. United States in the Lower Courts and the Emerging Carpenter Test

Lawfare: The Impact of Carpenter v. United States in the Lower Courts and the Emerging Carpenter Test by Matthew Tokson:

The Supreme Court’s 2018 decision in Carpenter v. United States was widely considered to be a sea change in Fourth Amendment law. Carpenter held that individuals can retain Fourth Amendment rights in information they disclose to a third party, at least in some situations. Specifically, cell phone users retained Fourth Amendment rights in their cell phone location data, even though that data was disclosed to their cell phone companies.

This is a potentially revolutionary holding in the internet era, when virtually every form of sensitive digital information is exposed to a third-party service provider at some point. Carpenter raises the possibility that the Fourth Amendment may effectively protect sensitive digital data. But Carpenter is a notoriously vague opinion, and scholars have reached conflicting conclusions about its meaning and impact. What does Carpenter mean, and what will it mean in the future?

In a recent article forthcoming in the Harvard Law Review, I attempt to shed some light on Carpenter and its jurisprudential impact. I coded and analyzed all 857 federal and state judgments applying Carpenter through March 31, 2021. In doing so, I was able to identify the factors that drive modern Fourth Amendment search decisions and describe a nascent Carpenter test now emerging in the lower courts. I also examined overall compliance with Carpenter, finding that courts have largely embraced it, with almost no overt criticism and relatively little indirect noncompliance. And I encountered a shockingly high rate of cases resolved based on the “good faith exception” to the exclusionary rule, which permits the government to use unconstitutionally obtained evidence to convict defendants if such evidence was collected in reliance on prior law. These findings can help resolve some of the mysteries of Carpenter, illuminating both the present state of the law and the paths along which it will likely continue to develop.

Fascinating:

Matthew J. Tokson, The Aftermath of Carpenter: An Empirical Study of Fourth Amendment Law, 2018-2021 (September 28, 2021). Harvard Law Review, Forthcoming, University of Utah College of Law Research Paper No. 470, Available at SSRN: https://ssrn.com/abstract=3932015. Abstract:

Fourth Amendment law is in flux. The Supreme Court recently established, in the landmark case Carpenter v. United States, that individuals can retain Fourth Amendment rights in information they disclose to a third party. In the internet era, this ruling has the potential to extend privacy protections to a huge variety of sensitive digital information. But Carpenter is also notoriously vague. Scholars and lower courts have tried to guess at what the law of Fourth Amendment searches will be going forward—and have reached different, contradictory conclusions.

This Article reports the results of a large-scale empirical study of the impact of a transformative Supreme Court decision in federal and state courts. It analyzes all 857 federal and state judgments applying Carpenter from its publication in June 2018 through March 2021. Relying on this unique, hand-coded database, the Article illuminates both the present and future of Fourth Amendment law.

In doing so, it identifies the factors that drive modern Fourth Amendment search decisions—and those that fail to drive them. It examines disagreements among lower courts about the scope and breadth of Carpenter, as some courts apply its concepts expansively while others attempt to narrow it from below. It assesses how state courts apply federal constitutional law, blending federal and state interests in unique ways. And it analyzes the enormous practical impact of the “good faith exception” to the exclusionary rule, which permits the government to use unconstitutionally obtained evidence to convict defendants if such evidence was collected in reliance on prior law. Based on these findings, the Article explores alternative directions that courts may take as they continue to refine Fourth Amendment law and address novel surveillance technologies. In addition to its many contributions to the Fourth Amendment literature, the Article is the most comprehensive empirical study to date of the jurisprudential impact of a Supreme Court case in the years following its publication.