What Is a Search? The Basics

The Fourth Amendment is short, just 54 words, and it reflects the desires of those who wrote and ratified it to protect Americans against unreasonable government intrusion into their lives. The Amendment mentions some of the more important aspects of a person’s life—her house, her papers, her effects, even her “person,” that is, her body—and declares that government agents may not unreasonably search or seize those things. Here is the text: 

“The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.” 

These words have inspired arguments about their meanings. For example, what counts as a “house” and thereby merits protection from unreasonable searches? Is it limited to physical buildings in which people live, or is some area outside the structure included? We will see later that the Court eventually defined the concept of “curtilage,” which is an outdoor area that the Court treats as part of the “house.” 

Over the coming weeks, students will encounter vigorous debate over the meaning of “reasonable.” When is it reasonable for a police officer to stop and frisk a pedestrian about whom the officer has suspicion? When is it reasonable for police to search cars without warrants? For now, we will set aside the concept of reasonableness for one simple reason: Before something can be an “unreasonable search,” it must first be a “search.” The cases assigned for this chapter concern the definition of “search” for purposes of Fourth Amendment jurisprudence. (Similarly, before something can be an “unreasonable seizure,” it must first be a “seizure.” We will consider the definition of “seizure” later in the semester.) 

To key elements are important for understanding the concept of a “search” and judges’ approach to deciding whether actions by government—especially the police as government officials—violate the Fourth Amendment’s protection against “unreasonable searches.”  First, the existence of a government action that is defined as a search is typically defined as an intrusion that violates an individual’s “reasonable expectation of privacy.”  If someone is walking in the open down a public sidewalk and a police officer watches the person from across the street, that is not a search. It would not be reasonable for an individual to consider it an intrusion for someone to see them when they have placed themselves in a public place that is visible to others.  On the other hand, if a police officer pressed her face against the window of a house in order to try to look through a narrow opening in a close curtain, that is quite different with respect to it impact on an individual’s reasonable expectation of privacy. 

Second, judges generally evaluate claims about Fourth Amendment violations through a balancing test that asks whether the individual’s interest in privacy in a specific situation outweighs the importance of the government’s interest in intruding on the individual’s expectation of privacy.   Thus, when people boarding a commercial flight must walk through a metal detector, the government’s interest in preventing people from bringing weapons or bombs on planes—in order to prevent hijackings and other life-threatening dangers—outweighs the minimal intrusion of having a machine detect whether an individual is carrying a weapon under her clothing.  By contrast, if school officials strip search students looking for missing pencil, the government’s interest in a low-value, non-dangerous item would not justify such a severe intrusion on the students’ reasonable expectation of privacy.  Thus, this latter example would violate Fourth Amendment rights.