Which case permits police to stop and frisk someone based on reasonable suspicion?

The case that permits police to stop and frisk someone based on reasonable suspicion is Terry v. Ohio. This landmark decision established that law enforcement officers have the authority to stop a person for questioning and conduct a limited frisk of their outer clothing if they have a reasonable suspicion that the individual may be armed and involved in criminal activity. The ruling emphasizes the balance between the need for police officers to ensure their safety during encounters and the Fourth Amendment right against unreasonable searches and seizures.

In this case, the court recognized that while a stop and frisk is a form of search, if police have specific and articulable facts that suggest a person is dangerous, it is a justified measure designed to prevent potential harm. This decision laid the groundwork for the practice of stop-and-frisk, solidifying the concept of reasonable suspicion as a critical threshold for such police actions.