concurring.
I join the opinion of the Court. With respect to its effect on respondent’s “right... to be secure ... in [his] perso[n]” guaranteed by the Fourth Amendment, the stop in this case — although it no doubt seriously infringed upon respondent’s privacy — lasted a mere matter of moments, see ante, at 224-225, before the discovery of the gun ripened what had been merely reasonable suspicion into the full-scale probable cause necessary for an arrest. For circumstances like these, Terry v. Ohio, 392 U. S. 1 (1968), “defined a special category of Fourth Amendment ‘seizures’ so substantially less intrusive than arrests that the general rule requiring probable cause to make Fourth Amendment ‘seizures’ reasonable could be replaced by a balancing test.” Dunaway v. New York, 442 U. S. 200, 210 (1979). See ante, at 228. Such a balancing test is appropriate as long as it is conducted with full *237regard for the serious privacy interests implicated even by such a relatively nonintrusive stop. See Terry v. Ohio, supra. Of course, in the case of intrusions properly classifiable as full-scale arrests for Fourth Amendment purposes, no such balancing test is needed. Such arrests are governed by the probable-cause standard provided by the text of the Fourth Amendment itself.