The Fourth Amendment Categorical Imperative

Abstract

In an effort to bring the Fourth Amendment into the twentieth century, the Court formulated a brand-new definition of “search” in Katz v. United States based on reasonable expectations of privacy. Although perhaps progressive for its time, the Katz definition of “search” has rendered the Fourth Amendment nearly moot in the twenty-first century. That is because modern tracking, surveillance, data aggregation, and data analysis technologies — all of which engage in “searches” by any common definition — exploit information in which, the Court has held, we do not have reasonable expectations of privacy. As a consequence, searches conducted using these means and methods are not regulated by the Fourth Amendment because they are not regarded as “searches” at all.

In 2012 the Court indicated that it was inclined to revisit or revise Katz. It appears poised to do just that during the October 2017 term, but has yet to signal where it might go or why. This essay, which is available on the Michigan Law Review website, offers a way forward that relies on the text and history of the Fourth Amendment and insights from Immanuel Kant to provide a concise test the Court can apply to determine when the Fourth Amendment restrains the otherwise unfettered discretion of government agents to engage in searches and seizures.

Keywords: Fourth Amendment, Originalism, Cell Site Location Information, Categorical Imperative