This litigation began in 1971, when inmates sued the Suffolk County sheriff, the Commissioner of Correction for the State of Massachusetts, the Mayor of Boston, and nine city councilors, claiming that inmates not yet convicted of the crimes charged against them were being held under unconstitutional conditions at what was then the Suffolk County Jail. The Court permanently enjoined the government defendants: '(a) from housing at the Charles Street Jail after November 30, 1973 in a cell with another inmate, any inmate who is awaiting trial and (b) from housing at the Charles Street Jail after June 30, 1976 any inmate who is awaiting trial.' The defendants did not appeal. In 1977, with the problems of the Charles Street Jail still unresolved, the District Court ordered defendants, including the Boston City Council, to take such steps and expend the funds reasonably necessary to renovate another existing facility as a substitute detention center. The Court of Appeals ordered that the Charles Street Jail be closed on October 2, 1978, unless a plan was presented to create a constitutionally adequate facility for pretrial detainees in Suffolk County. The Court eventually allowed Suffolk County to continue housing its pretrial detainees at the Charles Street Jail. Seven months later, the Court entered a formal consent decree in which the government defendants expressed their 'desire . . . to provide, maintain and operate as applicable a suitable and constitutional jail for Suffolk County pretrial detainees.' The decree specifically incorporated the provisions of the Suffolk County Detention Center, Charles Street Facility, Architectural Program, which - in the words of the consent decree - 'sets forth a program which is both constitutionally adequate and constitutionally required.' During the intervening years, the inmate population outpaced population projections. Litigation in the state courts ensued, and defendants were ordered to build a larger jail. Thereupon, plaintiff prisoners, with the support of the sheriff, moved the District Court to modify the decree to provide a facility with 435 cells. The number of cells was later increased to 453. Construction started in 1987. In July 1989, while the new jail was still under construction, the sheriff moved to modify the consent decree to allow the double-bunking of male detainees in 197 cells, thereby raising the capacity of the new jail to 610 male detainees. The sheriff argued that changes in law and in fact required the modification. The asserted change in law was this Court's 1979 decision in Bell v. Wolfish, 441 U.S. 520 (1979), handed down one week after the consent decree was approved by the District Court. The asserted change was the increase in the population of pretrial detainees. The District Court refused to grant the requested modification, holding that the sheriff had failed to meet the standard of ***United States v. Swift & Co., 286 U.S. 106, 119 : (1932): 'Nothing less than a clear showing of grievous wrong evoked by new and unforeseen conditions should lead us to change what was decreed after years of litigation with the consent of all concerned.'*** The court refused to order modification because of the increased pretrial detainee population, finding that the problem was 'neither new nor unforeseen.' The Court of Appeals affirmed. In moving for modification of the decree, the sheriff relied on Federal Rule of Civil Procedure 60(b), which in relevant part provides: 'On motion and upon such terms as are just, the court may relieve a party or a party's legal representative from a final judgment, order, or proceeding for the following reasons: . . . (5) the judgment has been satisfied, released, or discharged, or a prior judgment upon which it is based has been reversed or otherwise vacated, or it is no longer equitable that the judgment should have prospective application; or (6) any other reason justifying relief from the operation of the judgment. . . .