502us2$26I 02-19-99 14:01:15 PAGES OPINPGT Cite as: 502 U. S. 367 (1992) 405 Stevens, J., dissenting IV The motion to modify that ultimately led to our grant of certiorari was filed on July 17, 1989. As I view these cases, the proponents of that motion had the burden of demonstrating that changed conditions between 1985 and 1989 justified a further modification of the consent decree. The changes that occurred between 1979 and 1985 were already reflected in the 1985 modification. Since petitioners acquiesced in that modification, they cannot now be heard to argue that pre-1985 developments—either in the law or in the facts— provide a basis for modifying the 1985 order. It is that order that defined petitioners’ obligation to construct and to operate an adequate facility. Petitioners’ reliance on Bell v. Wolfish, 441 U. S. 520 (1979), as constituting a relevant change in the law is plainly misplaced. That case was pending in this Court when the consent decree was entered in 1979. It was the authority on which the sheriff relied when he sought permission to double cell in 1984, and, of course, it was well known to all parties when the decree was modified in 1985. It does not qualify as a changed circumstance.5 room shall contain high quality washing and clothes drying equipment, sink, sorting table, storage and ironing board.’ ” Id., at 17a, 18a. 5 As the Court agrees that Bell v. Wolfish did not constitute a change in law requiring modification of the decree, see ante, at 388, the Court does not define further the kind of changes in law that may merit modification. In particular, the Court has no occasion to draw a distinction between the type of change in law recognized in Railway Employes v. Wright, 364 U. S. 642 (1961), and the change in law that petitioners assert was effected by Bell. The distinction is nevertheless significant and deserves mention. In Railway Employes, the plaintiffs originally brought suit, alleging that a railroad and its unions discriminated against nonunion employees, a practice prohibited by the Railway Labor Act, 45 U. S. C. § 151 et seq. The defendants entered into a consent decree, promising to refrain from such discrimination. When Congress subsequently amended the Act to permit union shops, the Court concluded that a modification allowing union shops should be granted so as to further the statutory purpose. In contrast to the situation presented in Railway Employes, it cannot be con-