This was a class action brought under 42 U.S.C. § 1983 challenging the manner in which the County of Riverside, California (D), provides probable cause determinations to persons arrested without a warrant. D combined probable cause determinations with its arraignment procedures. Arraignments must be conducted without unnecessary delay and, in any event, within two days of arrest but the two-day requirement excluded from computation weekends and holidays. Over the Thanksgiving holiday, a 7-day delay was possible. For those arrested for felonies up to 10 days delay was a reality. In August 1987, Donald Lee McLaughlin (P) filed a complaint in District Court seeking injunctive and declaratory relief on behalf of himself and '`all others similarly situated.'' P was then currently incarcerated in the Riverside County Jail and had not received a probable cause determination. He requested 'an order and judgment requiring that D provide in-custody arrestees, arrested without warrants, prompt probable cause, bail and arraignment hearings.' P moved for class certification. D moved to dismiss the complaint, asserting that P lacked standing to bring the suit because he had failed to show that he would again be subject to the allegedly unconstitutional conduct - i.e., a warrantless detention without a probable cause determination. The District Court certified a class comprising 'all present and future prisoners in the Riverside County Jail. Ps then asked the District Court to issue a preliminary injunction requiring the County to provide all persons arrested without a warrant a judicial determination of probable cause within 36 hours of arrest. The District Court adopted a rule that the County provide probable cause determinations within 36 hours of arrest, except in exigent circumstances. The court 'retained jurisdiction indefinitely' to ensure that the County established new procedures that complied with the injunction. The Ninth Circuit consolidated this case with another challenging an identical preliminary injunction issued against the County of San Bernardino. The Court of Appeals affirmed the order granting the preliminary injunction against Riverside County. The Court of Appeals rejected D's standing argument, holding that the named plaintiffs had Article III standing to bring the class action for injunctive relief. At the time, Ps filed their complaint, they were in custody and suffering injury as a result of D's allegedly unconstitutional action. The court then proceeded to the merits and determined that D's policy of providing probable cause determinations at arraignment within 48 hours was 'not in accord with Gerstein's requirement of a determination `promptly after arrest,'' because no more than 36 hours were needed 'to complete the administrative steps incident to arrest.' The Ninth Circuit thus joined the Fourth and Seventh Circuits in interpreting Gerstein as requiring a probable cause determination immediately following completion of the administrative procedures incident to arrest. D appealed. The Supreme Court granted certiorari to determine what constitutes a 'prompt' probable cause determination under Gerstein.