What defines the outer limits of what an officer can do during a Terry frisk?

During a Terry frisk, which arises from the Supreme Court case Terry v. Ohio, the primary purpose is to ensure the safety of the officer and others by allowing them to pat down a suspect for weapons. The outer limits of what an officer can do during this type of stop are strictly defined by the need to discover weapons or items that could be used as weapons.

The rationale behind this practice is rooted in the need for immediate and practical safety concerns during investigative stops where the officer suspects that a person may be armed and dangerous. The frisk is a limited search; it does not extend to seeking out evidence of criminal activity in general, nor can it involve looking for stolen items or investigating personal documents such as a driver’s license. Instead, it is narrowly focused on the potential for immediate danger presented by armed suspects. This focus ensures that the search remains reasonable in scope and tied directly to the officer's concern for safety.