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Unreasonable Search (Update)


"Unreasonable search and seizure" is a technical phrase that refers to any governmental search and seizure deemed to violate the fourth amendment of the Constitution. In general, searches and seizures are unreasonable if the government undertakes them without properly authorizing search warrants or, in exceptional circumstances not requiring warrants, in violation of the rules laid down for those exceptions. The Fourth Amendment provides, "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." The amendment defines neither "unreasonable" nor "searches and seizures," and the judiciary has taken on the task of definition. The Supreme Court has concluded that particularized searches and seizures with a warrant, as called for by the amendment's warrant clause, establish the norm for reasonableness. It is the neutral, detached, judicial determination of good reason or "probable cause" to search foror seize particular persons or things in particular places that makes such acts presumptively "reasonable." Unauthorized searches and seizures, unless specially justified, are generally thought unreasonable.

Although searches and seizures based on proper warrants are the accepted constitutional norm, not all warrantless searches and seizures violate the Fourth Amendment. They do not if they are directed at objects or interests the amendment does not protect, if they do not constitute "searches" or "seizures" in the legal sense, or if they fall within one of the recognized exceptions to the warrant or probable cause requirements.

In katz v. united states (1967), the Supreme Court stated that the Fourth Amendment, among other things, protected certain individual interests in privacy from unreasonable government search and seizure. Subsequent opinions have said the amendment protects an individual's reasonable expectation of privacy, a test involving both a subjective expectation of privacy and one that society is prepared to recognize as "reasonable." Where an individual has no reasonable expectation of privacy, the government may search and seize without a warrant and even without probable cause. Consequently, the government may search and seize things or matters that an individual of necessity or willingly exposes to the public. For example, the government may photograph one's features, lift one's fingerprints, tape public lectures, or place tracking devices on cars.

The second part of the Katz test requires that the expectation of privacy be one that society—here represented by the Supreme Court—is prepared to recognize as reasonable. One consequence of the Court's "reasonable expectation" definitions has been that police may freely examine some places where people might actually expect some privacy, at least in the sense of not contemplating that the government would seek evidence against them there. For example, the Court has held that persons have no reasonable expectation of privacy in trash placed out for collection. The Court has also held, in effect, that persons have no expectation that items hidden from ordinary view on real property will be free from aerial surveillance. Finally, it has held that an occupant of real property has an expectation of privacy only with regard to his or her home and its "curtilage," or the area immediately surrounding it and associated with intimate home uses. Consequently, even were one to hide something in dense, secluded woods on one's private property, the government could legitimately search the woods without a warrant or probable cause.

There are a number of recognized exceptions to the warrant requirement and even some to the probable cause requirement. These exceptions are made in situations in which, while the police have probable cause to search for and seize particular evidence or persons in particular places, some other circumstance—usually referred to as an "exigent" or emergency circumstance—makes it impossible, impracticable, self-defeating, or unwise to obtain a warrant. In situations in which the government demonstrates a special and important need for a limited search, the reasonableness of the search depends upon a balancing of the need to search against the intrusion the search entails. For such reasons, the Court has held several kinds of warrantless searches reasonable: searches incident to arrest; investigative stops-and-frisks; automobile searches and searches of other mobile vehicles; inspection and regulatory searches, including border searches; some employer drug-testing searches; and consent searches.

An arrest is a seizure of a person. Under common law and constitutional rule, when police see a crime being committed or have probable cause to think that a specific person has committed a felony and may escape unless arrested, they may arrest without a warrant. Arrest may place police officers at risk if the person arrested has a weapon, and one arrested may wish to dispose of incriminating evidence. To protect themselves and others and to prevent destruction of evidence, officers arresting on probable cause may conduct a full body search of the arrestee and the area within his or her ready reach.

In contrast, warrantless searches and seizures within a home are presumptively unreasonable. Consequently, when police have probable cause to arrest someone who is at home and unlikely to flee while a warrant is sought, they must obtain an arrest warrant.

There are police-civilian encounters short of arrest, usually called "investigative detentions" or "stops-and-frisks." Police rightly investigate suspicious circumstances or characters, and good police work may entail stopping and questioning persons on some reasonable suspicion. If police do stop someone to investigate, however, they may place themselves at risk if the person carries a weapon. On the other hand, a general police authority to stop and question anyone for any reason opens possibilities of police harassment. The Court has held therefore that although the procedure entails a seizure and a search, it is reasonable for officers to stop persons they reasonably suspect of criminal activity and of being armed and dangerous, for the purpose of questioning them and searching for weapons. Under this authority, when police have reasonable suspicion to think that luggage, parcels, or other containers contain contraband or evidence of a crime, they may detain them for a limited, unintrusive inspection, such as sniffing by a trained narcotics-detection dog.

Mobile vehicles present a special problem. Were police to seek a warrant for a vehicle they have probable cause to suspect contains evidence of a crime, the vehicle might leave the jurisdiction in the interim. In addition, as the Court has held, because of extensive regulation of vehicles and the character of their public uses, there is a lesser expectation of privacy in vehicles than there is in homes or offices. Consequently, the Court has laid down the rule that when police have probable cause regarding a mobile vehicle, they may undertake a warrantless search of it. The authority remains even if the vehicle is unlikely to be moved or the police have immobilized it.

Governments undertake inspection or regulatory searches for a variety of purposes. Fire inspection codes often require home and building safety inspection. Airline safety dictates some inspection of luggage and persons flying. Entry into an agricultural pest quarantine zone calls for inspection for designated pests. Crossing an international border calls for inspection to ensure right of entry and search to ensure against smuggling of contraband or dutiable goods. In these situations, the need to inspect or search is great, any inconvenience is small, and the scope and the extent of associated interrogation and search is limited. Similarly, public safety or security may require mandatory drug testing for railway or airline employees where their inattention or dereliction of duty would involve an immediate risk of serious harm. In general, the combination of an overriding public interest and the relatively limited character of the search are thought to make such searches reasonable.

Consent searches constitute the final major exception to the warrant and probable cause requirements. Individuals may voluntarily waive their constitutional rights. One can therefore give up the search and seizure protections the Fourth Amendment accords by agreeing to a search. The major questions in such a case are whether there was voluntary consent to the search and whether the party consenting had authority to do so. Whether consent was voluntary or coerced is a factual question, but the state need not show that the person who allegedly gave consent knew that he or she had a right to refuse to give consent. The Court has also indicated that anyone who has common authority over premises or effects can consent to a search of them and that such consent holds against an absent nonconsenting person who shares the authority. In other words, third parties, who are not the targets of a search, can sometimes consent to searches aimed at securing evidence against a target.

Gary Goodpaster

(see also: Exigent Circumstances Search; Open Fields Doctrine; Plain View Doctrine.)


Amsterdam, Anthony 1974 Perspectives on the Fourth Amendment. Minnesota Law Review 58:349–477.

La Fave, Wayne 1987 Search and Seizure: A Treatise on the Fourth Amendment, 3 vols. St. Paul, Minn.: West Publishing Co.

Landynski, J. 1966 Search and Seizure and the Supreme Court. Johns Hopkins University Studies in Historical and Political Science, ser. 84, No. 1.

Taylor, Telford 1969 Two Studies in Constitutional Interpretation. Columbus: Ohio State University Press.

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