When Queries Become Clues: Keyword Search Warrants and the Modern Fourth Amendment

Rory Owens*

This Note addresses the constitutional questions that keyword search warrants have created in light of modern Fourth Amendment jurisprudence.⁹ Part I provides an overview of current Fourth Amendment doctrine, outlining the modern privacy-based framework, the third-party doctrine, Carpenter v. United States, and the core requirements of probable cause and particularity. Part II introduces keyword search warrants as a new form of reverse search warrant. It defines how they operate and highlights two recent state court cases that address their constitutionality. Part III offers a constitutional analysis of keyword search warrants. Section III.A argues that obtaining a user’s query data—even if partially de-identified—constitutes a “search” under Carpenter, given how extensively it can reveal an individual’s private life. Section III.B contends that keyword search warrants are not per se invalid: when tailored to specific times, locations, and search terms, they can satisfy both probable cause and particularity.

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*J.D. Candidate, Notre Dame Law School, 2026. I am grateful to Dennis Wieboldt and John Gatt for their feedback, as well as to my colleagues on the Notre Dame Law Review for their careful edits.

9 This Note analyzes keyword search warrants within the Supreme Court’s existing Fourth Amendment jurisprudence. The focus is descriptive rather than prescriptive; it seeks to explain how these warrants are evaluated under current doctrine, not to advance an independent theory of Fourth Amendment meaning.