Pennsylvania V. Mimms

The order to get out of the car, issued after the respondent was lawfully detained, was reasonable and thus permissible under the Fourth Amendment. The State's proffered justification for such order - the officer's safety - is both legitimate and weighty, and the intrusion into respondent's personal liberty occasioned by the order, being at most a mere inconvenience, cannot prevail when balanced against legitimate concerns for the officer's safety.

Under the standard announced in Terry v. Ohio, 392 U.S. 1, whether "the facts available to the officer at the moment of the seizure or the search “warrant a man of reasonable caution in the belief' that the action taken was appropriate" - the officer was justified in making the search he did once the bulge in respondent's jacket was observed.