The great majority of §1983 excessive force claims against the police arise out of use of force to effectuate an arrest. Some §1983 plaintiffs allege that the officer used excessive force in conducting an investigatory or traffic stop. A police arrest or stop is clearly a “seizure” within the meaning of the Fourth Amendment; police use of excessive force used to effectuate an arrest or stop renders the seizure unreasonable.

What if the officer’s use of force did not occur in the course of an arrest or stop? In these cases, a court has to decide the threshold question of whether the officer’s use of force constituted a “seizure.” If police action does not constitute a search or seizure, the Fourth Amendment does not apply.