Based on a standard which holds less than probable cause, this power is granted upon the standard of reasonable suspicion. It is a question of circumstances of each individual case that determines whether reasonable detention and investigation is validated.[7]
Legislation pertaining to constitutional requirements of stop and frisk practices were made into an area of concern by the Supreme Court when they encountered the case of Terry v. Ohio. While frisks were arguably illegal, before this point a police officer could only search someone either after arresting them or obtaining a search warrant. In the cases of Terry v. Ohio, Sibron v. New York, and Peters v. New York, the Supreme Court granted limited approval in 1968 to frisks conducted by officers lacking probable cause for an arrest in order to search for weapons if the officer believes the subject to be dangerous. The Court's decision made suspicion of danger to an officer grounds for a "reasonable search".[8]
Stop-and-frisk is not necessarily a new invention. In the early 1980s if a police officer had reasonable suspicion of a possible crime, he had the authority to stop someone and ask questions. If, based on the subject’s answers, the suspicion level did not escalate to probable cause for an arrest, the person would be released immediately. This was only a “stop-and-question". The “frisk” part of the equation did not come into play except on two occasions: (1)If possession of a weapon was suspected, or (2)if reasonable suspicion of a possible crime escalated to probable cause to arrest for an actual crime based on facts developed after the initial stop-and-question. That all changed in the 1990s when CompStat was developed under then Police Commissioner William Bratton. High-ranking police officials widely incorporated the “stop, question and frisk”.[9]
In 1990, William J. Bratton became head of the New York City Transit Police. Bratton described George L. Kelling as his "intellectual mentor", and implemented a zero tolerance policy because of his contributions to the development of the “broken windows theory”. Former mayor Rudy Giuliani, a Republican, hired Bratton as his police commissioner who adopted the strategy more widely for use in New York City. Giuliani used Bratton and the massive expansion of the New York police department to crack down on crimes. Giuliani's "zero-tolerance" included a crackdown on fare evasion, public drinking, public urination, graffiti artists and the “squeegee men" (who had been wiping windshields of stopped cars and aggressively demanding payment).[10]