concurring.
I join the Court’s opinion with the understanding that it merely holds, under the peculiar facts here, that the State “must be recognized as a joint participant in the challenged activity.” See Burton v. Wilmington Parking Authority, 365 U. S. 715, 725 (1961). Deputy Sheriff Collins, an agent of the State, was regularly employed by Glen Echo in the enforcement of its segregation policy. I cannot, therefore, say, as does my Brother Harlan, that the situation “is no different from what it would have been had the arrests been made by a regular policeman dispatched from police headquarters.” Here Collins, the deputy sheriff, ordered petitioners to leave the park before any charges were filed. Upon refusal, Collins, the deputy sheriff, made the arrest and then took petitioners to the police station where he filed the charges and secured the warrant. If *138Collins had not been a police officer, if he had ordered the petitioners off the premises and filed the charges of criminal trespass, and if then, for the first time, the police had come on the scene to serve a warrant issued in due course by a magistrate, based on the charges filed, that might be a different case. That case we do not pass upon.