FOURTH AMENDMENT

The Fourth Amendment to the U.S. Constitution reads:

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 American Revolution was fought, in part, to create a system of government in which the rule of law would reign supreme. The rule of law is often identified with the old saying that the United States is a nation of laws and not of men. Under the rule of law, the actions of government officials are prescribed by the principles and laws that make up the U.S. legal system and do not reflect the arbitrary whims and caprices of the government officials themselves.

A distinction is sometimes drawn between power and authority. Law enforcement officers are entrusted with the powers to conduct investigations, to make arrests, and occasionally to use lethal force in the line of duty. But these powers must be exercised within the parameters authorized by the law. Power exercised outside of these legal parameters transforms law enforcers into lawbreakers, as happened when Los Angeles police officer Laurence Powell was convicted for using excessive force against rodney king, who had been stopped for speeding. Powell repeatedly struck King with his night-stick even though King was in a submissive position, lying prone on the ground.

The Fourth Amendment was intended to create a constitutional buffer between U.S. citizens and the intimidating power of law enforcement. It has three components. First, it establishes a privacy interest by recognizing the right of U.S. citizens to be "secure in their persons, houses, papers, and effects." Second, it protects this privacy interest by prohibiting searches and seizures that are "unreasonable" or are not authorized by a warrant based upon probable cause. Third, it states that no warrant may be issued to a law enforcement officer unless that warrant describes with particularity "the place to be searched, and the persons or things to be seized."

The Framers drafted the Fourth Amendment in response to their colonial experience with British officials, whose discretion in collecting revenues for the Crown often went unchecked. Upon a mere suspicion held by British tax collectors or their informants, colonial magistrates were compelled to issue general warrants, which permitted blanket door-to-door searches of entire neighborhoods without limitation as to person or place. The law did not require magistrates to question British officials regarding the source of their suspicion or to make other credibility determinations.

The writ of assistance was a particularly loathsome form of general warrant. The name of this writ derived from the power of British authorities to enlist local peace officers and colonial residents who might "assist" in executing a particular search. A writ of assistance lasted for the life of the king or queen under whom it was issued, and it applied to every officer and subject in the British Empire. In essence, such a writ was a license for customs officers tracking smugglers and illegally imported goods.

Colonial opposition to general warrants was pervasive and kinetic. In Paxton's Case (also known as the writs of assistance case), 1 Quincy 51 (Mass. 1761), james otis, appearing on behalf of colonists who opposed the issuance of another writ of assistance, denounced general warrants as instruments of "slavery," "villainy," and "arbitrary power." These writs, Otis continued, were "the most destructive of English liberty" because they placed the freedom of every person "in the hands of a petty officer" (as quoted in O'Rourke v. City of Norman, 875 F.2d 1465 [10th Cir. 1989]). In order to be valid, Otis railed, a warrant must be "directed to specific officers, and to search certain houses" for particular goods, and may only be granted "upon oath made" by a government official "that he suspects such goods to be concealed in those very places he desires to search" (as quoted in Illinois v. Krull, 480 U.S. 340, 107 S. Ct. 1160, 94 L. Ed. 2d 364 [1987]).

Although Otis lost the case, his arguments fueled angry colonial crowds that subsequently interfered with British customs and revenue agents who attempted to seize miscellaneous goods pursuant to general warrants. Some provincial courts began declining to issue writs of assistance, and other courts issued writs with greater specificity. Colonial newspapers complained that British officers were ransacking the colonists' houses, violating the sanctity of their bedrooms, and plundering their privacy under the auspices of general warrants. On the night before the Declaration of Independence was published, john adams cited the "argument concerning the Writs of Assistance … as the commencement of the controversy between Great Britain and America."

The American Revolution answered the questions surrounding writs of assistance, but the Fourth Amendment raised other questions in the newly founded republic. If a police officer's suspicion is no longer sufficient to obtain a search warrant, as it was in colonial America, where should the line be drawn separating suspicion from probable cause? Although general warrants are now clearly prohibited, how detailed must warrants be to pass constitutional muster? The Fourth Amendment expressly forbids "unreasonable" searches and seizures, but what criteria should be considered in evaluating the reasonableness of a search? The Fourth Amendment also leaves open the question of who should review warrant applications—the judiciary or some other branch of government. The answers to these questions were explored and developed in criminal litigation over the next two centuries.

Fourth Amendment questions arise during criminal litigation in the context of a suppression hearing. This hearing is prompted by a defendant who asks the court to review the method by which the police obtained evidence against him or her, and to determine whether that evidence survives constitutional scrutiny. If the evidence was obtained in violation of the Fourth Amendment, it usually will be excluded from trial, which means the prosecution will be unable to present it to the jury. The legal doctrine under which illegally obtained evidence is suppressed is known as the exclusionary rule, and its purpose is to deter police misconduct and to protect defendants from it.

The exclusionary rule requires the suppression not only of evidence that was the direct product of illegal police work but also of any evidence that is derived from a tainted source. The suppression of tainted derivative evidence, also known as fruit of the poisonous tree, typically occurs when the police obtain a confession after an illegal arrest or pursuant to an unconstitutional search. Although the manner in which the confession itself was obtained may have been perfectly constitutional, the confession is still suppressed because the law does not permit the government, which the prosecution represents at a criminal trial, to benefit from its own misconduct.

Before a court may exclude any evidence, it first must determine whether the Fourth Amendment even applies to the case under consideration. Two requirements must be met before a particular search or seizure will give rise to Fourth Amendment protection. First, the search or seizure must have been conducted by a government agent or pursuant to government direction. Thus, the actions of state and federal law enforcement officers or private persons working with law enforcement officers will be subject to the strictures of the Fourth Amendment. Bugging, wire tapping, and other related eavesdropping activities performed by purely private citizens, such as private investigators, will not receive Fourth Amendment protection.

Second, a defendant must be able to demonstrate that he or she had a "reasonable expectation of privacy" in the place that was searched or the thing that was seized (Katz v. United States, 389 U.S. 347, 88 S. Ct. 507, 19 L. Ed. 576 [1967]). In Katz, the U.S. Supreme Court explained that "[w]hat a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection… . Butwhat he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected."

Applying this principle, the Court has ruled that U.S. citizens maintain a reasonable expectation of privacy in the "curtilage" immediately surrounding their home, but not in the "open fields" and "wooded areas" extending beyond this area (Hester v. United States, 265 U.S. 57, 44S. Ct. 445, 68 L. Ed. 898 [1924]). A person may have a reasonable expectation of privacy in the automobile that he or she is driving, but not in items that are in "plain view" from outside the vehicle (Coolidge v. New Hampshire, 403 U.S. 443, 91 S. Ct. 2022, 29 L. Ed. 564 [1971]). Nor do people have reasonable expectations of privacy in personal characteristics (United States v. Dionisio, 410 U.S. 1, 93 S. Ct. 764, 35 L. Ed. 2d 67[1973]). Thus, the police may require individuals to give handwriting and voice exemplars as well as fingerprint samples, without complying with the Fourth Amendment's warrant or reasonableness requirements.

In Minnesota v. Carter, 525 U.S. 83, 119 S. Ct. 469, 142 L. Ed.2d 373 (1998), the U.S. Supreme Court considered whether a police officer who had looked in an apartment window through a gap in a closed window blind had violated the privacy of the drug dealers in the apartment because they had an expectation of privacy that is protected by the Fourth Amendment. The Court held that the police officer had not violated the Fourth Amendment because the occupants of the apartment had not had an expectation of privacy. This was due to the fact the drug dealers had merely used the apartment to consummate business transactions and that they had no personal relationship with the occupant of the apartment.

However, the high court looked at the issue differently when the drug courier's contraband was discovered on a bus by an officer who thought that a bag felt peculiar. In Bond v. U.S., 529 U.S. 334, 120 S. Ct. 1462, 146 L. Ed.2d 365(2000), it ruled that police cannot squeeze the luggage of bus passengers in order to try to find illegal drugs. The ruling forces law enforcement to modify the way they inspect luggage and packages that are carried by, or in the custody of an individual.

The U.S. Supreme Court has made clear that there are limits to high-tech government snooping when the government has the ability to use sophisticated technology to monitor criminal suspects. In Kyllo v. United States, 533 U.S. 27, 121 S. Ct. 2038, 150 L. Ed.2d 94 (2001), the Court ruled that police could not use evidence obtained through the use of thermal imaging without first obtaining a search warrant. It declared that a warrantless search would be regarded as "presumptively unreasonable" and that the evidence that the search produced will be inadmissible at trial. The police had received a tip that Danny Kyllo was growing marijuana inside his home. Because marijuana cultivation requires the use of high-intensity lamps, police used a thermal imager to scan Kyllo's residence. The imager detects infrared radiation, which is invisible to the naked eye. The machine converts the radiation into images based on relative warmth. The police conducted the scan across the street from Kyllo's home, accomplishing the task in just a few minutes. The scan disclosed that one part of his house was substantially hotter than any other unit in his triplex. Based on the scan, utility bills, and tips from informants, police secured a search warrant and found that Kyllo had indeed been growing marijuana.

The U.S. Supreme Court noted that the degree of privacy guaranteed by the Fourth Amendment had been affected by technological developments. The question became "what limits there are upon this power of technology to shrink the realm of guaranteed privacy." In its view, individuals had a "minimum expectation of privacy"that the interiors of their homes were not subject to warrantless police searches."Thus, the use of "sense-enhancing technology" that could obtain information that would otherwise only be obtainable by a physical search constituted a "search." Accordingly, any information obtained by the thermal imager was the product of a search. The Court's analysis led to the legal conclusion that such a search was unreasonable and that it could be justified only if it were made pursuant to a warrant.

Once a court has determined that the Fourth Amendment is an issue in a particular case, it next must decide whether law enforcement complied with the amendment's requirements. When making this decision, a court begins with the premise that the Constitution expresses a preference for searches made pursuant to a warrant (Mincey v. Arizona, 437 U.S. 385, 98 S. Ct. 2408, 57 L. Ed. 2d 290 [1978]). Searches performed without a warrant are presumptively invalid, and evidence seized during a warrantless search is suppressed unless the search was reasonable under the circumstances.

The U.S. Supreme Court has ruled that warrantless searches may be deemed reasonable in certain situations. First, no warrant is required for searches incident to a lawful arrest (United States v. Watson, 423 U.S. 411, 96 S. Ct. 820, 46 L. Ed. 2d 598 [1976]). If a police officer has probable cause to believe that a crime has occurred, the Fourth Amendment permits the officer to arrest the suspect and to conduct a search of the suspect's person and clothing and of all areas within the suspect's immediate reach. Second, a police officer who possesses an "articulable" and "reasonable" suspicion that an automobile has violated a state or local traffic law may stop the driver and conduct a search of the vehicle's interior, including the glove compartment (Delaware v. Prouse, 440 U.S. 648, 99 S. Ct. 1391, 59 L. Ed. 2d 660 [1979]). The trunk of a vehicle cannot be searched unless an officer has probable cause to believe that it contains contraband or the instrumentalities of criminal activity.

Third, an officer who reasonably believes "that criminal activity may be afoot" in a public place may stop an individual who is suspected of wrongdoing and "conduct a carefully limited search of [the suspect's] outer clothing" for weapons that may be used against the officer (terry v. ohio, 392 U.S. 1, 88 S. Ct. 1868, 21 L. Ed. 889 [1968]). Fourth, officers who are in "hot pursuit" of "fleeing felons" or are gathering "evanescent" evidence (evidence that could readily disappear—e.g. blood samples from drunken drivers) are also permitted to act without first obtaining a search warrant.

These four exceptions to the warrant requirement are based on the need to facilitate law enforcement during unforeseen or emergency circumstances in which criminal activity is strongly suspected but police officers lack sufficient time to complete an application for a search warrant and to testify before a magistrate. These exceptions also reflect a need to protect police officers from hidden weapons and to preserve evidence that easily could be destroyed or compromised.

When law enforcement does obtain a warrant before conducting a search, the warrant must comply with the Fourth Amendment before evidence from the search will be admissible in court. A warrant may be defective if it is not supported by probable cause that is established by a detailed, sworn statement made by a law enforcement officer appearing before a magistrate.

No definition of probable cause has ever satisfied both prosecutors and defense attorneys. But the U.S. Supreme Court has said that probable cause exists where "the facts and circumstances within [the police officer's] knowledge" are of a "reasonably trustworthy" basis to "warrant a man of reasonable caution" to believe that an offense has been or is about to be committed (Carroll v. United States, 267 U.S. 132, 45 S. Ct. 280, 69 L. Ed. 543 [1925]). Probable cause can be established by out-of-court statements of reliable police informants even though the credibility of those statements cannot be tested by a magistrate (Illinois v. Gates, 462 U.S. 213, 103 S. Ct. 2317, 76 L. Ed. 2d 527 [1983]). However, probable cause will not be found where the only evidence of criminal activity is an officer's "good information" or "belief" (Aguilar v. Texas, 378U.S. 108, 84 S. Ct. 1509, 12 L. Ed. 2d 723 [1964]).

The Fourth Amendment requires not only that search warrants be supported by probable cause but also that they "particularly" describe the person or place to be searched. A warrant must provide enough detail so that an "officer with the search warrant can, with reasonable effort, ascertain and identify the place [or person] intended" (Steele v. United States, 267 U.S. 498, 45 S. Ct. 414, 69 L. Ed. 757 [1925]). For most residences, a street address usually satisfies the particularity requirement. However, if a warrant designates an apartment complex, hotel, or other multiple-unit building, the warrant must describe the specific sub-unit that will be searched. When a warrant designates that a person will be searched, it must include a description that provides enough detail so that the suspect's identity can be ascertained with reasonable certainty.

Probable cause must be established by testimony made under oath by a law enforcement officer appearing before a magistrate. The testimony can be oral or written, and it cannot contain any "knowingly" or "intentionally" false statements, or statements made in "reckless disregard for the truth" (Franks v. Delaware, 438U.S. 154, 98 S. Ct. 2674, 57 L. Ed. 2d 667 [1978]). Inaccuracies due to negligence or innocent omission do not jeopardize a warrant's validity.

The magistrate before whom an officer applies for a warrant must be "neutral and detached" (Coolidge v. New Hampshire, 403 U.S. 443, 91 S. Ct. 2022, 29 L. Ed. 2d 564 [1971]). This means that the magistrate must be impartial and not a member of the "competitive enterprise" of law enforcement (California v. Acevedo, 500 U.S. 565, 111 S. Ct. 1982, 114 L. Ed. 2d 619 [1991]). Thus, police officers, prosecutors, and attorneys general are disqualified from the role of magistrate. However, judges, lawyers, and court clerks all potentially qualify as "neutral and detached," and therefore may become magistrates. The requirements that states set for becoming a magistrate vary widely, from having an attorney's license to having a high-school diploma to simply being literate.

If a search is performed pursuant to a defective warrant, any evidence obtained as a result of the search is usually suppressed. An exception to this rule arises when an officer has obtained evidence pursuant to a defective warrant that the officer relied on in "good faith" (United States v. Leon, 468 U.S. 897, 104 S. Ct. 3430, 82 L. Ed. 2d 677 [1984]). For this exception to apply, the warrant must have been issued by a magistrate and then later ruled defective for a valid reason, and the defect must not have been the result of willful police deception. If these two requirements are satisfied, law enforcement was entitled to rely on the warrant in conducting the search, and any evidence obtained during the search is admissible against the defendant.

This exception was created to ensure that police officers would not be punished for blunders made by magistrates when issuing search warrants. Again, the primary reason courts suppress illegally obtained evidence is to deter future police misconduct. No deterrent value is served by excluding evidence obtained by an honest police officer who acted pursuant to an ostensibly valid warrant that was later ruled defective owing to an error by the magistrate.

The U.S. Supreme Court also has been asked to determine whether the way in which a search with a warrant is conducted can violate the Fourth Amendment. One troublesome area has been the question of whether police must knock on a suspect's door and announce that they have a warrant, in order to enter the premises lawfully. The general rule is that police may make a "no-knock" entry if there are reasonable grounds for such a course of action. In Richardsv. Wisconsin, 520 U.S. 385, 117 S. Ct. 1416, 137 L. Ed. 615 (1997), the U.S. Supreme Court was confronted with a decision of the Wisconsin Supreme Court that announced a blanket exception to the knock-and-announce requirement for felony drug investigations. The high court unanimously ruled that such an exception violated the Fourth Amendment and that it undermined the ability of a reviewing court to determine whether a particular no-knock entry had been reasonable. In making this ruling, the Court rejected the idea that the violent world of narcotics traffickers justified a departure from Fourth Amendment jurisprudence.

One year later, the U.S. Supreme Court clarified the standards to which police will be held when they execute "no-knock" searches, in U.S.v. Ramirez, 523 U.S. 65, 118 S. Ct. 992, 140 L. Ed.2d 191 (1998). It held that the Fourth Amendment does not hold officers to a higher standard when a "no-knock" entry results in the destruction of property. In Ramirez,a federal district court suppressed two weapons that had been seized as evidence because the police officers had violated the Fourth Amendment and 18U.S.C.A. § 3109, which permits federal law enforcement officers to damage property in certain instances. The Court acknowledged that excessive or unnecessary destruction of property during a search could be a violation of the Fourth Amendment "even though the entry itself is lawful and the fruits of the search not subject to suppression." However, in that case, the officers' actions had been reasonable, based on an informant's information, as the officers had not wanted the suspect to seek out the weapons.

Police often justify a search and seizure by stating that the suspect consented. Again, the U.S. Supreme Court has had to determine the boundaries of consent. In U.S. v. Drayton, 536 U.S. 194, 122 S. Ct. 2105, 153 L. Ed.2d 242 (2002), the Court reviewed an Eleventh Circuit Court of Appeals decision that invalidated the pat-down search of two defendants who had been on a cross-country bus trip, even though both defendants had consented to the search. The appeals court concluded that the circumstances surrounding the search had not been sufficiently free of coercion to serve as a constitutional basis for the search. The high court reversed the decision, holding that police officers on public transportation do not need to inform each passenger that they have the right to refuse a search, pat-down, or questioning in order for the investigation to remain constitutional. It deemed the distinction between the confines of a bus and the open spaces of the street to be immaterial to the reasons why citizens choose to cooperate or not. Presumably, citizens "know that their participation enhances their own safety and the safety of those around them."

Individuals who are on probation typically sign an agreement that allows police to enter their homes in order to ensure that they are complying with the terms of probation. Questions have arisen over when police may search a probationer for another crime if the person has signed a probation agreement that permits such searches. Police and government officials have argued that they may conduct a search without a warrant if they believe that the suspect has committed a new crime. Criminal defendants have argued that probation agreements that require them to submit to searches at anytime only apply to searches that have a probationary purpose rather than an investigatory purpose. The U.S. Supreme Court, in United States v. Knights, 534 U.S.112, 122 S. Ct. 587, 151 L. Ed.2d 497 (2002), declined to issue a bright-line rule on this dispute but concluded that when police have reasonable suspicion and the probation agreement authorizes searches, the search is reasonable under the Fourth Amendment. Instead, the Court applied its traditional analysis for judging whether a warrantless search was reasonable. This "totality of the circumstances" approach looks at the intrusion of individual privacy and contrasts it with "legitimate governmental interests."

further readings

Brandveen, Antonio I. 1998. "Criminal Profiling Treads Too Heavily on Fourth Amendment Rights." New York Law Journal (September 9).

Cunningham, Clark D. 1988. "A Linguistic Analysis of the Meanings of 'Search' in the Fourth Amendment: A Search for Common Sense." Iowa Law Review 73.

Gearan, Anne. 2001. "Police Need Warrant to Use Heat Sensors." Chicago Daily Law Bulletin (June 11).

LaFave, Wayne, and Jerald Israel. 1992. Criminal Procedure. 2d ed. St. Paul, Minn.: West/Wadsworth.

Levy, Leonard. 1988. Original Intent and the Framers' Constitution. New York: Macmillan.

O'Neill, Timothy P. 2001."4th Amendment Test Needs Overhaul Based on Trust." Chicago Daily Law Bulletin (July 13).

cross-references

Criminal Law; Criminal Procedure; Mapp v. Ohio; Stop and Frisk.

Fourth Amendment While investigating crime, police detain or arrest persons, frisk for weapons, and search for incriminating evidence or contraband such as illegal drugs. Other government officials, ranging from regulators to school principals, conduct a wide variety of inspections. The Fourth Amendment to the federal Constitution is the principal legal limitation on government arrest, search, and inspection authority. It is enforced primarily by an exclusionary rule that sometimes prohibits the use as evidence of items or information obtained in violation of Fourth Amendment standards. At various points during the twentieth century it appeared that the Supreme Court might fashion the amendment into a comprehensive regulation of government intrusions into citizens' liberty and privacy, but decisions since the early 1970s have undercut that potential, and the protections afforded by the amendment are now rather limited.

History

The Fourth Amendment was prompted by a prerevolutionary controversy over the legality of “general warrants.” A warrant is a command from a judge ordering an officer to arrest a person or search a place for evidence or contraband. However, because a general warrant did not specify who was to be arrested or what place was to be searched it conferred discretionary search authority on peace officers. Because discretionary arrest or search authority conflicted with common‐law standards, in the 1760s English courts declared such warrants illegal. Nevertheless, in 1767 Parliament reauthorized customs officers in the American colonies to use a form of general warrant called a “writ of assistance.” However, American colonial courts generally refused to issue such writs, and sometimes denounced them as illegal. On independence, several states included bans against general warrants in state declarations of rights, and the Fourth Amendment was included in the federal Bill of Rights to prohibit Congress from ever authorizing general warrants.

For various reasons, the amendment was not construed by the Supreme Court until Boyd v. United States when, in 1886, the justices interpreted the reference to a right against “unreasonable searches and seizures” in the amendment as a broad “reasonableness” requirement for government searches and struck down a statute on that basis. There was still hardly any litigation regarding searches until after the 1914 decision in Weeks v. United States. In that decision, the Court held both that a warrantless search of a house by a federal marshal violated the amendment and that the items that were seized unconstitutionally would be inadmissible as evidence in legal proceedings—what became known as the exclusionary rule. Because exclusion gave defendants an incentive to challenge searches, search litigation increased dramatically after Weeks. During the early twentieth century, the Supreme Court developed the elements of modern search‐and‐seizure law while reviewing lower court decisions regarding admissibility of evidence seized in police searches.

Fourth Amendment Reasonableness

During the twentieth century, the justices continued to interpret the amendment as setting a broad “reasonableness” requirement for government intrusions. Although some historical treatments of the amendment assumed that this reading reflected the intended meaning of the text, it now appears that the amendment was actually intended only to ban general warrants. Instead, the Fifth Amendment was meant to regulate the initiation of criminal prosecutions and the common‐law standards for warrantless arrests and searches—standards more rigorous than “reasonableness”—were understood to be components of the “due process of law” required by that amendment. Thus “unreasonable searches and seizures” in the Fourth Amendment was simply a pejorative label for the gross illegality of general warrant searches. However, the original meanings of both amendments were lost during the nineteenth century as courts relaxed common‐law standards to make it easier for newly created police departments to maintain order in a rapidly urbanizing society.

The modern reasonableness standard necessarily involves balancing personal rights to liberty and privacy against the government's interest in effective law enforcement. Unsurprisingly, that balance has shifted as the justices' ideological commitments and social concerns have changed. When the Supreme Court initially applied the Fourth Amendment in the early twentieth century, it treated the amendment as applying only to searches and arrests by federal officers. Moreover, the justices were especially concerned with protecting business records. The justices interpreted the reasonableness standard to mean that it usually was unreasonable for police to search private property without previously obtaining a warrant. Searches pursuant to warrants were preferred because it was assumed magistrates were less likely to approve of poorly justified intrusions.

By the amendment's terms, a warrant must be supported by a sworn showing of “probable cause” and must particularly identify the place to be searched and the items or persons to be seized. Traditionally, “probable cause” meant that a person who asked a magistrate to issue a warrant had to swear to personal knowledge of facts sufficient to warrant a prudent man in the belief that the person to be arrested had committed a crime (for an arrest warrant) or that evidence of a crime or contraband would be found in the place to be searched (for a search warrant). The particularity requirement is usually satisfied if a search warrant states the address of a building to be searched and identifies the general nature of the contraband or evidence sought.

However, the warrant requirement was never absolute. Even at common law, peace officers could sometimes make warrantless arrests and they could also search the person arrested if there was reason to think that the arrestee had a weapon or that he might possess evidence of the crime for which they had been arrested. In addition, during Prohibition, the justices ruled in Carroll v. United States (1925) that, because a vehicle could be driven away while police were obtaining a warrant, the exigency involved made it reasonable for police to search a vehicle thoroughly without a warrant if they had probable cause to believe the vehicle contained contraband.

During the 1940s and 1950s, the warrant requirement was undercut when justices advanced a competing generalized‐reasonableness interpretation of the amendment. In cases such as United States v. Rabinowitz (1950), a divided Court sometimes permitted warrantless searches of even entire residences in which an arrest had been made. In addition, although some justices began to advocate applying the Fourth Amendment and the exclusionary rule to the states through the Fourteenth Amendment incorporation doctrine, a majority of the justices rejected that change, and the Fourth Amendment was still applied only to federal searches.

Warren Court

During the 1960s, the Warren Court reinvigorated and extended the amendment's protections in several respects. Most importantly, in 1961 in Mapp v. Ohio the Court incorporated the Fourth Amendment into the Fourteenth Amendment and thus, made state searches that did not comply with Fourth Amendment standards subject to the exclusionary rule. In addition, the Warren Court renewed the earlier emphasis on search warrants. Thus, when the justices expanded the scope of the amendment's protections beyond property concerns to cover private phone conversations in Katz v. United States (1967), they also required that police obtain warrants for wiretaps. However, by the 1960s, search warrants were often issued based upon police reports of hearsay information from unidentified informants. The Warren Court attempted to give the warrant requirement more substance by ruling, in Spinelli v. United States (1969), that police had to provide magistrates with certain information about the informants who provided information used for probable cause.

In addition, in an attempt to create a standard for police “stop and frisk” practices during street encounters, the Warren Court ruled that the Fourth Amendment applied to such police conduct in Terry v. Ohio (1968), but also ruled that such stops were valid if the police had “reasonable suspicion,” a less demanding standard than probable cause.

Shift toward Law Enforcement Interests

During the 1968 presidential election, Richard Nixon campaigned against the criminal procedure rulings of the Warren Court. During his first term as president, Nixon appointed four justices who were critical of Warren Court rulings, including Chief Justice Warren Burger and Justice William Rehnquist (who later became chief justice). Since the early 1970s, a majority of justices in the Burger and Rehnquist Courts have favored law enforcement interests over protection of citizens' liberty or privacy. Although those Courts have not overruled major Warren Court rulings, they have created numerous limitations and exceptions to the amendment's protections which, taken together, have drastically limited the amendment's protections.

Standing Requirement

Soon after Weeks, lower federal courts developed a “standing” requirement that prevented a defendant from challenging the admission of evidence seized by police unless a search had intruded upon his own premises or property, and the justices later acquiesed in that doctrine. Under that test, police are able to deliberately violate person A's privacy to obtain evidence against B, because B usually cannot challenge the search of A's property (United States v. Payner, 1980). Thus, the Burger Court ruled that passengers in automobiles may not challenge a search of the vehicle (Rakas v. Illinois, 1978); however, guests in a residence usually still may challenge a search of the residence (Minnesota v. Carter, 1998).

Scope of Protection

Not all police interactions with individuals involve searches or seizures. A person is not “seized” if police approach him or her in a public place and ask questions; rather, there is a seizure only if a reasonable person would not feel free to go on his or her way (Florida v. Bostick, 1991). Likewise, police investigation constitutes a “search” only if it intrudes upon a person's “reasonable expectation of privacy.” There cannot be an expectation of privacy in “open fields”—outside areas other than the “curtilage” immediately around a house (Oliver v. United States, 1984). In addition, the protection of the amendment is lost if a person exposes information or fails to adequately maintain privacy. Thus, the amendment does not protect bank records because that information has been exposed to the banker (United States v. Miller, 1976) or garbage set out for collection (California v. Greenwood, 1988). Likewise, if marijuana plants in a fenced yard can be seen from a helicopter, privacy is lost and the discovery is deemed to be “in plain view” (Florida v. Riley, 1989). Similarly, a sniff by a police dog trained to detect drugs is not deemed a search, so the government does not have to justify use of a drug dog (United States v. Place, 1983). In addition, like other constitutional rights, the protections afforded by the amendment can be waived if a person consents to a search. The justices do not require police to have suspicion prior to seeking consent or to inform the person that he or she can refuse to consent (Schneckloth v. Bustamonte, 1973). A large proportion of searches are conducted pursuant to consent.

Standards

The Court still requires police to obtain a warrant to enter a residence unless there is an emergency situation or consent has been given (Payton v. New York, 1980), and also limits technological surveilances of houses (Kyllo v. United States, 2001). However, warrants are now rarely required except for residences.

In the 1983 decision Illinois v. Gates, the justices also made it easier for police to obtain warrants by significantly relaxing the probable cause standard to a totality of the circumstances analysis of whether information indicated a “fair probability” of crime. That standard also makes it easier for police to justify warrantless arrests or searches of vehicles under the Carroll doctrine.

Police now also have broad authority to temporarily detain persons under the Terry reasonable suspicion standard (Alabama v. White, 1990). That standard also authorizes police to “frisk” a person for weapons if there is reasonable suspicion the person might be dangerous, and police also may frisk a car for weapons on the same basis (Michigan v. Long, 1983) as well as conduct a “protective sweep” of a house they have lawfully entered to locate persons who might pose a danger (Maryland v. Buie, 1990). If police come across evidence or contraband in the course of such frisks or sweeps, they may legally seize it as being in plain view.

In addition, police automatically may search a person who has been arrested for any offense (United States v. Robinson, 1973), and also may automatically search the passenger compartment of any vehicle that an arrested person has recently exited (Belton v. New York, 1981). This search incident to arrest authority is especially significant because the amendment does not bar custodial arrests for even the most minor traffic offenses (Atwater v. City of Lago Vista, 2001), and police are authorized to make pretextual stops or arrests for traffic violations in order to investigate other crimes (Whren v. United States, 1996). Hence, there is very little protection of privacy in a vehicle, and police engaged in criminal law enforcement often may bypass standards for detentions, arrests, or searches simply by following a car until the driver commits a traffic violation. In addition, police may make an inventory search of an arrested person's possessions or an impounded vehicle (Florida v. Wells, 1990).

Exclusion

In addition to relaxing search and arrest standards, the Burger and Rehnquist Courts have also limited the operation of the exclusionary rule. In 1974 in United States v. Calandra the Court repudiated the understanding that exclusion was a constitutional right of the victim of an unconstitutional search and redefined exclusion as only a policy aimed at deterring future police illegality. Because critics of the rule had asserted that exclusion was ineffective as a deterrent, that redefinition initially appeared to herald abolition of the rule. However, the justices did not go that far. Instead, subsequent decisions have limited the operation of the rule to the prosecutor's case‐in‐chief in a criminal trial, but permit use of unconstitutionally seized items for other purposes in criminal proceedings. For example, prosecutors can use unconstitutionally obtained evidence to impeach a defendant who testifies in his own defense (United States v. Havens, 1980). The justices have also created several exceptions that allow the government to freely use certain kinds of unconstitutionally obtained evidence even in the prosecutor's case‐in‐chief in a criminal trial. For example, the justices ruled in United States v. Leon (1984) that evidence seized under unconstitutionally issued warrants is almost always admissible under a “good‐faith mistake exception” (See Good Faith Exception) because the illegal warrant is the fault of the issuing magistrate rather than the police. Thus, the illegality of a search warrant usually no longer matters. However, the Court has not recognized any exception for misapplication of legal standards by police themselves in warrantless searches. The Court has also recognized an “inevitable discovery” doctrine that allows use of unconstitutionally discovered evidence if the government can show it is more likely than not that police would have found that evidence legally had they not already discovered it unconstitutionally (Murray v. United States, 1988). Taken collectively, these limitations on exclusion severely limit enforcement of Fourth Amendment protections, and unconstitutionally seized evidence is seldom excluded in serious prosecutions.

Moreover, alternative remedies for unconstitutional police intrusions are quite limited. Absent police brutality, the qualified‐official‐immunity doctrine usually protects police from civil damages lawsuits for illegal arrests or searches (Anderson v. Creighton, 1987). Likewise, the justices generally have not allowed use of injunctions against abusive police practices (Los Angeles v. Lyons, 1983). Hence, government violations of the Fourth Amendment now often have no legal consequence.

“Special Needs” Searches

Government officers or employees other than police sometimes conduct searches or inspections for purposes other than ordinary criminal law enforcement. Such searches usually are subject to the amendment, but the reasonableness of such searches is assessed according to the “special needs” of the particular context: for example, effective regulatory enforcement, public safety, or the preservation of discipline in educational institutions. Such searches usually do not require probable cause and in some instances special needs permit random searches not based on any individualized suspicion, such as vehicle checkpoints to identify inebriated drivers (Michigan Department of State Police v. Sitz, 1990) or drug testing of students (Board of Education v. Earls, 2002).

Conclusion

After three decades of decisions that have relaxed standards and curtailed enforcement, the Fourth Amendment now provides only marginal protection of individual privacy and liberty. Moreover, it seems unlikely that the Court will enhance the amendment's protection in the foreseeable future. Rather, attempts to prevent terrorism after the attacks of 11 September 2001 may result in further curtailments of those protections that still exist. For example, antiterrorism legislation has loosened restrictions on wiretaps and has authorized novel forms of searches such as “sneak‐and‐peak” warrants that permit police to surreptitiously enter and search a residence without giving notice to the residents that the search ever occurred. The Supreme Court has not yet addressed the constitutionality of these practices under the Fourth Amendment.

See also Search Warrant Rules, Exceptions to.

Bibliography

Thomas Y. Davies , Recovering the Original Fourth Amendment, Michigan Law Review 98 (1999): 547–750.
Thomas Y. Davies , The Fictional Character of Law‐and‐Order Originalism, Wake Forest Law Review 37 (2002): 239–437.
Joshua Dressler , Understanding Criminal Procedure, 3rd ed. (2002).
Wayne R. LaFave , Search and Seizure: A Treatise on the Fourth Amendment, 3rd ed. (1996).
Jacob Landynski , Search and Seizure and the Supreme Court (1966).

Thomas Y. Davies

Jacob Landynski