The Supreme Court case that defined "Stop and Frisk" and permitted temporary detentions based upon reasonable suspicion was

The Supreme Court case that defined "Stop and Frisk" and permitted temporary detentions based upon reasonable suspicion was "Terry v. Ohio". This case was decided in 1968.

Here are the steps that led to this decision:

1. The case began when a police officer observed three men acting suspiciously; they were walking back and forth in front of a store, which led the officer to believe they were planning a robbery.

2. The officer approached the men and identified himself, then performed a quick search of the men (a "stop and frisk") and found weapons on two of them.

3. The men were convicted based on the evidence found during the frisk, but they appealed their convictions, arguing that the search violated their Fourth Amendment rights (which protect against unreasonable searches and seizures).

4. The case eventually made its way to the Supreme Court, which had to decide whether the officer's actions were justified.

5. The Court ruled in an 8-1 decision that the officer had acted reasonably, given his suspicions and the potential threat to public safety. This established the principle that police can stop and frisk individuals if they have reasonable suspicion that the person has committed, is committing, or is about to commit a crime.

6. This case, Terry v. Ohio, thus defined the "stop and frisk" procedure and set the standard for when such searches are permissible under the Fourth Amendment.