Earl Warren

“ The protective search for weapons, on the other hand, constitutes a brief, though far from inconsiderable, intrusion upon the sanctity of the person. It does not follow that because an officer may lawfully arrest a person only when he is apprised of facts sufficient to warrant a belief that the person has committed or is committing a crime, the officer is equally unjustified, absent that kind of evidence, in making any intrusions short of an arrest. ”

“ No judicial opinion can comprehend the protean variety of the street encounter, and we can only judge the facts of the case before us. Nothing we say today is to be taken as indicating approval of police conduct outside the legitimate investigative sphere. Under our decision, courts still retain their traditional responsibility to guard against police conduct which is over-bearing or harassing, or which trenches upon personal security without the objective evidentiary justification which the Constitution requires. ”

“ Proper adjudication of cases in which the exclusionary rule is invoked demands a constant awareness of these limitations. The wholesale harassment by certain elements of the police community, of which minority groups, particularly Negroes, frequently complain, [11] will not be stopped by the exclusion of any evidence from any criminal trial. Yet a rigid and unthinking application of the exclusionary rule, in futile protest against practices which it can never be used effectively to control, may exact a high toll in human injury and frustration of efforts to prevent crime. ”

“ And it is nothing less than sheer torture of the English language to suggest that a careful exploration of the outer surfaces of a person's clothing all over his or her body in an attempt to find weapons is not a 'search,' Moreover, it is simply fantastic to urge that such a procedure performed in public by a policeman while the citizen stands helpless, perhaps facing a wall with his hands raised, is a 'petty indignity.' [13] It is a serious intrusion upon the sanctity of the person, which may inflict great indignity and arouse strong resentment, and it is not to be undertaken lightly. ”

“ Upon suspicion that the person may be armed, the police should have the power to 'frisk' him for weapons. If the 'stop' and the 'frisk' give rise to probable cause to believe that the suspect has committed a crime, then the police should be empowered to make a formal 'arrest,' and a full incident 'search' of the person. This scheme is justified in part upon the notion that a 'stop' and a 'frisk' amount to a mere 'minor inconvenience and petty indignity,' [4] which can properly be imposed upon the citizen in the interest of effective law enforcement on the basis of a police officer's suspicion. ”

“ It is quite plain that the Fourth Amendment governs 'seizures' of the person which do not eventuate in a trip to the station house and prosecution for crime-'arrests' in traditional terminology. It must be recognized that whenever a police officer accosts an individual and restrains his freedom to walk away, he has 'seized' that person. ”

“ One general interest is of course that of effective crime prevention and detection; it is this interest which underlies the recognition that a police officer may in appropriate circumstances and in an appropriate manner approach a person for purposes of investigating possibly criminal behavior even though there is no probable cause to make an arrest. ”

“ When an officer is justified in believing that the individual whose suspicious behavior he is investigating at close range is armed and presently dangerous to the officer or to others, it would appear to be clearly unreasonable to deny the officer the power to take necessary measures to determine whether the person is in fact carrying a weapon and to neutralize the threat of physical harm. ”

“ It is contended with some force that there is not-and cannot be-a variety of police activity which does not depend solely upon the voluntary cooperation of the citizen and yet which stops short of an arrest based upon probable cause to make such an arrest. The heart of the Fourth Amendment, the argument runs, is a severe requirement of specific justification for any intrusion upon protected personal security, coupled with a highly developed system of judicial controls to enforce upon the agents of the State the commands of the Constitution. ”

“ An arrest is a wholly different kind of intrusion upon individual freedom from a limited search for weapons, and the interests each is designed to serve are likewise quite different. An arrest is the initial stage of a criminal prosecution. ”

“ In view of these facts, we cannot blind ourselves to the need for law enforcement officers to protect themselves and other prospective victims of violence in situations where they may lack probable cause for an arrest. ”

“ Doubtless some police 'field interrogation' conduct violates the Fourth Amendment. But a stern refusal by this Court to condone such activity does not necessarily render it responsive to the exclusionary rule. Regardless of how effective the rule may be where obtaining convictions is an important objective of the police, [10] it is powerless to deter invasions of constitutionally guaranteed rights where the police either have no interest in prosecuting or are willing to forgo successful prosecution in the interest of serving some other goal. ”

“ The exclusionary rule has its limitations, however, as a tool of judicial control. It cannot properly be invoked to exclude the products of legitimate police investigative techniques on the ground that much conduct which is closely similar involves unwarranted intrusions upon constitutional protections. Moreover, in some contexts the rule is ineffective as a deterrent. Street encounters between citizens and police officers are incredibly rich in diversity. ”

“ Courts which sit under our Constitution cannot and will not be made party to lawless invasions of the constitutional rights of citizens by permitting unhindered governmental use of the fruits of such invasions. Thus in our system evidentiary rulings provide the context in which the judicial process of inclusion and exclusion approves some conduct as comporting with constitutional guarantees and disapproves other actions by state agents. ”

“ A ruling admitting evidence in a criminal trial, we recognize, has the necessary effect of legitimizing the conduct which produced the evidence, while an application of the exclusionary rule withholds the constitutional imprimatur. ”

“ The distinctions of classical 'stop-and-frisk' theory thus serve to divert attention from the central inquiry under the Fourth Amendment-the reasonableness in all the circumstances of the particular governmental invasion of a citizen's personal security. 'Search' and 'seizure' are not talismans. ”

“ Certainly it would be unreasonable to require that police officers take unnecessary risks in the performance of their duties. American criminals have a long tradition of armed violence, and every year in this country many law enforcement officers are killed in the line of duty, and thousands more are wounded. ”

“ The Fourth Amendment provides that 'the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated * * *.' This inestimable right of personal security belongs as much to the citizen on the streets of our cities as to the homeowner closeted in his study to dispose of his secret affairs. ”

“ Moreover, a perfectly reasonable apprehension of danger may arise long before the officer is possessed of adequate information to justify taking a person into custody for the purpose of prosecuting him for a crime. ”

“ They range from wholly friendly exchanges of pleasantries or mutually useful information to hostile confrontations of armed men involving arrests, or injuries, or loss of life. Moreover, hostile confrontations are not all of a piece. Some of them begin in a friendly enough manner, only to take a different turn upon the injection of some unexpected element into the conversation. Encounters are initiated by the police for a wide variety of purposes, some of which are wholly unrelated to a desire to prosecute for crime. ”

“ Nonetheless, the notions which underlie both the warrant procedure and the requirement of probable cause remain fully relevant in this context. In order to assess the reasonableness of Officer McFadden's conduct as a general proposition, it is necessary 'first to focus upon the governmental interest which allegedly justifies official intrusion upon the constitutionally protected interests of the private citizen,' for there is 'no ready test for determining reasonableness other than by balancing the need to search (or seize) against the invasion which the search (or seizure) entails.' Camara v. ”

“ It is intended to vindicate society's interest in having its laws obeyed, and it is inevitably accompanied by future interference with the individual's freedom of movement, whether or not trial or conviction ultimately follows. ”

“ It was this legitimate investigative function Officer McFadden was discharging when he decided to approach petitioner and his companions He had observed Terry, Chilton, and Katz go Through a series of acts, each of them perhaps innocent in itself, but which taken together warranted further investigation. There is nothing unusual in two men standing together on a street corner, perhaps waiting for someone. Nor is there anything suspicious about people in such circumstances strolling up and down the street, singly or in pairs. Store windows, moreover, are made to be looked in. ”

“ However, the court denied the defendants' motion on the ground that Officer McFadden, on the basis of his experience, 'had reasonable cause to believe * * * that the defendants were conducting themselves suspiciously, and some interrogation should be made of their action.' Purely for his own protection, the court held, the officer had the right to pat down the outer clothing of these men, who he had reasonable cause to believe might be armed. ”

“ Or the police may be seeking to mediate a domestic quarrel which threatens to erupt into violence. They may accost a woman in an area known for prostitution as part of a harassment campaign designed to drive prostitutes away without the considerable difficulty involved in prosecuting them. Or they may be conducting a dragnet search of all teenagers in a particular section of the city for weapons because they have heard rumors of an impending gang fight.↑ See Tiffany, McIntyre & Rotenberg, supra, n. ”

“ The crux of this case, however, is not the propriety of Officer McFadden's taking steps to investigate petitioner's suspicious behavior, but rather, whether there was justification for McFadden's invasion of Terry's personal security by searching him for weapons in the course of that investigation. We are now concerned with more than the governmental interest in investigating crime ”

“ But the story is quite different where, as here, two men hover about a street corner for an extended period of time, at the end of which it becomes apparent that they are not waiting for anyone or anything; where these men pace alternately along an identical route, pausing to stare in the same store window roughly 24 times ”

“ Warner, The Uniform Arrest Act, 28 Va.L.Rev. 315 (1942) ; Note, Stop and Frisk in California, 18 Hastings L.J. 623, 629-632 (1967) .↑ People v. Rivera, supra, n. 3, at 447, 252 N.Y.S.2d, at 464, 201 N.E.2d, at 36.↑ The theory is well laid out in the Rivera opinion:↑ See, e.g., Foote, The Fourth Amendment: Obstacle or Necessity in the Law of Arrest?, 51 J.Crim.L.C. & P.S. 402 (1960) .↑ See n. 11, infra.↑ Brief for Respondent 2.↑ See L. Tiffany, D. McIntyre & D. Rotenberg, Detection of Crime: Stopping and Questioning, Search and Seizure, Encouragement and Entrapment 18-56 (1967) . ”