Kyllo V. United States and the Partial Ascendance of Justice Scalia's Fourth Amendment

Abstract

In Kyllo v. United States, the United States Supreme Court concluded that the thermal imaging of a home by law-enforcement officials was a "search" subject to the Fourth Amendment. The Court reached this conclusion by a five-to-four vote, with Justice Scalia writing for the majority. In reaching this conclusion, the Kyllo majority purported to rely on the well-established test of Katz v. United States, 389 U.S. 347 (1967), under which government conduct constitutes a search when it interferes with a person's reasonable expectation of privacy. This article argues, however, that the Kyllo majority actually departed from the Katz test, and that it did so to avoid the privacy-eroding effect of the test that Justice Scalia had criticized in a prior case, writing only for himself and Justice Thomas. Because Kyllo departs from the Katz test, it will be harder for the Court in future cases to use the Katz test - as Justice Scalia believes the test has been used in the past cases - to preserve what he regards as the overly broad presumption that all warrantless searches are unconstitutional. Thus, Kyllo reflects an ascendance of Justice Scalia's view of the Fourth Amendment. The ascendance is only partial, however, because it appears that a majority of the Court would still use the Katz test, rather than Justice Scalia's original-understanding approach, in some circumstances.