A Terry stop in the United States allows the police to briefly detain a person based on reasonable suspicion of involvement in criminal activity. ("In Terry v. Ohio, 392 U. S. 1, 30 (1968), we held that the police can stop and briefly detain a person for investigative purposes if the officer has a reasonable suspicion supported by articulable facts that criminal activity "may be afoot," even if the officer lacks probable cause.") Reasonable suspicion is a lower standard than probable cause which is needed for arrest. When police stop and pat-down a pedestrian, this is commonly known as a stop and frisk. When police stop an automobile, this is known as a traffic stop. If the police stop a motor vehicle on minor infringements in order to investigate other suspected criminal activity, this is known as a pretextual stop.
In the United States at the federal level, the Supreme Court has decided many cases that define the intersection between policing and the Fourth Amendment protection against unreasonable searches and seizures. However, Congress has not defined a baseline for police behavior. There has been some state action at both the legislative and judicial levels, and also some cities have passed laws on these issues.
Some law academics are concerned that jurisprudence permitting Terry stops does not account for possible implicit bias of officers, and that this possibly results in racially skewed decision-making. Communities that have high rates of incarceration may experience more intense and punitive policing and surveillance practices even during periods of time when general crime rates are decreasing.
Origins
Terry v. Ohio used only the "reasonableness clause" from the Fourth Amendment The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated,...Reasonableness ...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. Warrant
The concept of a Terry stop originated in the 1968 Supreme Court case Terry v. Ohio, in which a police officer detained three Cleveland men on the street behaving suspiciously, as if they were preparing for armed robbery. The police conducted a pat down search and discovered a revolver, and subsequently, two of the men were convicted of carrying a concealed weapon. The men appealed their case to the Supreme Court, arguing that the search in which the revolver was found was illegal under the Fourth Amendment. This brief detention and search were deemed permissible by the court, judging that the officer had reasonable suspicion which could be articulated (not just a hunch) that the person detained may be armed and dangerous. This was not mere "suspicion" but "reasonable suspicion" which could be articulated at a later date.
This decision was made during a period of great social unrest in the United States in the 1960s, with rising crime, opposition to U.S. involvement in the Vietnam War and the civil rights movement, and race riots. It was thought that law enforcement needed to be provided with tools to deal with the unrest and new issues of urban crime. Some criticized the decision for watering down the prohibition against unreasonable searches and seizures; others praised it for balancing safety and individual rights.
Elements
The United States Supreme Court held that where: a police officer observes unusual conduct by a subject; the subject's conduct leads the officer reasonably to conclude that criminal activity may be afoot, and that the subject may be armed and presently dangerous; the officer identifies themselves as a police officer; the officer makes reasonable inquiries; and nothing in the initial stages of the encounter serves to dispel the officer's reasonable fear for safety, the officer may conduct a carefully limited search of the outer clothing of the subject in an attempt to discover weapons, and that such a search is a reasonable search under the Fourteenth Amendment, so that any weapons seized may properly be introduced in evidence.Terry v. Ohio, 392 U.S. 1, 30–31 (1968).
Expansion through case law
Reasonable suspicion
To possess reasonable suspicion that would justify a stop, police must have "specific and articulable facts" that indicate that the person to be stopped is, or is about to be, engaged in criminal activity. Because officers usually do not have supervision when they encounter civilians, they have discretion regarding whom to stop. Reasonable suspicion depends on the "totality of the circumstances". Reasonable suspicion is a vague term, and the Supreme Court concluded that it is to be decided on a case-by-case basis. It often arises from a combination of facts, each of which would, in itself, not be enough justification for the stop.
Types of police-civilian encounters Consensual encounter Requires neither probable cause nor reasonable suspicion Terry stop (investigative detention) Requires reasonable suspicion Arrest Requires probable cause The suspicion must be that of an individual person. Police officers primarily use situational factors based on criminal behavior to determine whether a stop is needed. In essence, when they witness a person behaving suspiciously or violating the law, they are constitutionally permitted to stop them. Other factors informing the decision include personal attitudes and the decision-making model in effect where the officer works. These subjective influences naturally create the opportunity for bias on the part of police officers who possess animus toward a certain class of people.
The three types of primary sources that courts should accept in order to determine suspiciousness are information obtained from third parties, information based on the suspect's appearance and behavior and the time and place of the suspected offense. Officers can define what they believe is normal, and if and how the suspect deviates from this. Reasonable suspicion has been used for actions such as standing in the wrong place, nervousness, exceptional calmness or walking quickly in another direction. Officers' experiences may make them suspicious of behavior that is usually innocuous. For instance, a social interaction such as a hug or a handshake might be perceived as a drug deal. Merely identifying that a person belongs to a broad category, such as physical location, race, ethnicity or profile, is insufficient for reasonable suspicion. However, stop-and-frisk has been validated on the basis of furtive movements, inappropriate attire, carrying objects such as a television or a pillowcase (in English law, "going equipped"), vague, nonspecific answers to routine questions, refusal to identify oneself and appearing to be out of place.
Before 1968, the law required substantial evidence to impede liberty or seize property. However, the Fourth Amendment does not protect consensual encounters. In its Terry decision, the Supreme Court found that the police should have the power to search, even without probable cause, to protect themselves from weapons. The Terry stop operates under the assumption that although stop-and-frisk is an intrusion, the potential harm from weapons outweighs it.
The cases following Terry expanded the power of the police. While the original case was concerned with armed violence and firsthand observation by officers, Adams v. Williams (1972) extended the doctrine to drug possession substantiated by the secondhand hearsay of an informant. The Adams v. Williams case set a precedent that police are not required to directly observe suspicious behavior if their reasonable suspicion is based upon information provided by a confidential informant. Regarding the case, Justice Marshall stated: "Today's decision invokes the specter of a society in which innocent citizens may be stopped, searched, and arrested at the whim of police officers who have only the slightest suspicion of improper conduct." United States v. Hensley (1985) ruled that police officers may stop and question suspects whom they recognize from "wanted" flyers issued by other police departments. In Illinois v. Wardlow (2000), a person's unprovoked flight from Chicago police officers in "an area known for heavy narcotics trafficking" constituted reasonable suspicion to stop him.
During Terry stops, police usually ask detainees to identify themselves. Several states require people to provide their names to the police upon request. In Hiibel v. Sixth Judicial District Court of Nevada (2004), these stop-and-identify statutes were deemed constitutional. While the specifics of stop-and-identify statutes and ordinances vary, a significant number of states and local jurisdictions have enacted such laws. In New York, courts have limited the effects of Terry by creating a four-level continuum of intrusion, each of which requires its own level of suspicion. This allows police officers to detain people if the officers possess an articulable and objectively credible reason. In People v. DeBour, New York's highest court permitted the police to stop a person who simply crosses the street upon observing the police.
Lacking reasonable suspicion, police may stop a person based on a hunch, constituting a consensual stop. United States v. Mendenhall found that police are not generally required to advise an individual that the stop is on a consensual basis nor that the person may leave at any time.Writing for the court in United States v. Mendenhall, Justice Stewart stated, A person can typically determine whether a stop is consensual by asking, "Am I free to go?". If the officer responds in the negative or does not respond, the person is being detained under a Terry stop; otherwise, the person may leave. Mendenhall also found that a consensual stop can be converted into an unconstitutional Terry stop by circumstances such as "the threatening presence of several officers, the display of a weapon by an officer, some physical touching of the person of the citizen, or the use of language or tone of voice indicating that compliance with the officer's request might be compelled." Police who conduct an unconstitutional Terry stop can face administrative discipline and civil suits.
In Pennsylvania v. Mimms, two police officers issued Mimms a ticket for driving a car with an expired license plate. When they asked him to step out, they realized that he had a gun, and promptly arrested him. The court ruled in favor of the police, citing officer safety as their reason. Dissenting justices found that this furthers the expansion of Terry. They feared that the ruling set a precedent that officers could ask citizens to perform actions through warrantless intrusion.
Search
A frisk, also known as a pat-down, of the surface of a suspect's garments is permitted during a Terry stop but must be limited to actions necessary to discover weapons and must be based on a reasonable suspicion the individual may be armed. However, pursuant to the plain-feel doctrine (similar to the plain-view doctrine), police may seize contraband discovered in the course of a frisk, but only if the type of contraband is immediately apparent.
The Supreme Court has placed very liberal requirements on what is "immediately apparent" regarding contraband. In an example provided by the Federal Law Enforcement Training Centers, an officer feels a hard pack of cigarettes while frisking a suspect and inspects the pack, discovering drugs inside. The officer is legally permitted to open the pack because he has prior knowledge, based on experience, that a small switchblade or tiny gun could be hidden in such a box.