Medicaid is a cooperative federal-state program that provides federal funding for state medical services to the poor. State participation is voluntary; but once a State elects to join the program, it must administer a state plan that meets federal requirements. Each state must have an EPSDT. The EPSDT provisions of the Medicaid statute require participating States to provide various medical services to eligible children, and to provide notice of the services. Frew (Ps) mothers of children eligible for EPSDT services filed a civil action pursuant under 42 U. S. C. §1983, seeking injunctive relief against various Texas state officials. Ps alleged that the Texas program did not satisfy the requirements of federal law. Two Texas state agencies named in the suit moved to dismiss the claims against them on Eleventh Amendment grounds. The petitioners did not object, and the District Court dismissed the state agencies as parties. The state officials remained in the suit, and the District Court certified a class consisting of children in Texas entitled to EPSDT services, a class of more than 1 million persons. Following extensive settlement negotiations, Ps and the state officials agreed to resolve the suit by entering into a consent decree. The District Court conducted a fairness hearing, approved the consent decree, and entered it in 1996. The decree is a detailed document about 80 pages long that orders a comprehensive plan for implementing the federal statute. The consent decree requires the state officials to implement many specific procedures. Two years after the consent decree was entered, Ps filed a motion to enforce it in the District Court; The state officials (Ds) had not complied with the decree in various respects. Ds denied the allegations and maintained that the Eleventh Amendment rendered the decree unenforceable even if they were in noncompliance. The District Court issued a detailed opinion concluding that certain provisions of the consent decree had been violated. Ds filed an interlocutory appeal, and the Court of Appeals for the Fifth Circuit reversed. It held that the Eleventh Amendment prevented enforcement of the decree unless the violation of the consent decree was also a statutory violation of the Medicaid Act that imposed a clear and binding obligation on the State. The Court of Appeals concluded that because Ps had not established a violation of federal law, the District Court lacked jurisdiction to remedy the consent decree violations. Other Circuits have reached a contrary result, holding that the Eleventh Amendment does not bar enforcement of consent decrees in like circumstances. The Supreme Court granted certiorari.