What Constitutes a Search within the Meaning of the Fourth Amendment

Posted: 7 May 2010

See all articles by Thomas K. Clancy

Thomas K. Clancy

University of Mississippi School of Law

Date Written: 2006


The Fourth Amendment protects "[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures." In analyzing any Fourth Amendment issue, two separate questions must be answered: Is the Amendment applicable; and (2) If so, is it satisfied? To be applicable, a "search" or "seizure" must occur. This Article addresses the definition of a search. There are "few issues more important to a society than the amount of power that it permits its police to use without effective control." When it labels certain governmental quests to obtain evidence as not a search within the meaning of the Fourth Amendment, the Supreme Court insulates those activities from any judicial oversight.

Defining a search is a two-sided inquiry: governmental actions must invade a protected interest of the individual. If the individual does not have a protected interest, actions that might otherwise be labeled a search will not implicate the Fourth Amendment. If a person has a protected interest, then the focus turns to the governmental techniques used to obtain tangible things or information. Much has been written about what constitutes an individual’s protected interest, which the Court measures by utilizing the often-criticized reasonable expectation of privacy standard. This Article does not add to that discussion; instead, it assumes that the individual has a protected interest and focuses on the part of the inquiry that has often been neglected, that is, what governmental methods of obtaining tangible things or information are or should be considered invasions of the individual’s protected interest and, hence, a search within the meaning of the Fourth Amendment.

This Article first examines the historical background of the Fourth Amendment, emphasizing the physical intrusions that animated its adoption. It then details the Court’s treatment of the concept of a search, cataloguing both physical and non-physical governmental activities. The word "search" is a term of art in Fourth Amendment jurisprudence and is not used in its ordinary sense. The conclusion that a search has happened varies depending on the type of governmental activity utilized to obtain the evidence. That activity may include physical manipulation, visual observations, other use of the senses, and the employment of instrumentalities such as a dog’s nose or technological devices. In Supreme Court jurisprudence, physical manipulation by the police comes closest to a common sense understanding of what a search is. That literal view must be contrasted with other situations, particularly sense-enhancing devices where the legal definition is divorced from the ordinary meaning of the term, thus permitting the Court to conclude that no search has occurred. The use of technological devices to learn something that would not otherwise be discovered is so rapidly expanding that it is difficult to grasp the myriad ways the government can obtain tangible evidence or information. Therefore, it is essential that the Court provide a comprehensive definition of the concept of a search to ascertain when the Amendment is implicated by a device that the government employs.

This Article proposes that any intrusion with the purpose of obtaining physical evidence or information, either by a technological device or the use of the senses into a protected interest should be considered a search, and, therefore, must be justified as reasonable. As will be discussed, the definition proposed here is based on several considerations: an analogy to physical invasions, which is rooted in historical concerns and provides a workable standard; a need to inquire into the government’s purpose in engaging in the activity because the Amendment is only applicable to intentional governmental actions; the relevant inquiry is not whether significant or criminal facts are learned, but that something is learned as a result of an intrusion into the individual’s protected interest; there is no principled difference among sense-enhancing devices or their availability to the public; and finally, and most importantly, the Amendment’s fundamental purpose, which is to protect individuals from unreasonable governmental intrusions.

Keywords: Fourth Amendment, Criminal Procedure, Constitutional Law

Suggested Citation

Clancy, Thomas K., What Constitutes a Search within the Meaning of the Fourth Amendment (2006). Available at SSRN: https://ssrn.com/abstract=1602051

Thomas K. Clancy (Contact Author)

University of Mississippi School of Law ( email )

Lamar Law Center
P.O. Box 1848
University, MS 38677
United States
662-832-5244 (Phone)

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