Municipalities can be held liable for violations of Constitutional rights through 42 U.S.C. § 1983 actions. §1983 claims against municipal entities must be based on implementation of a policy or custom. Decided June 6, 1978 (argued November 2, 1977). Opinion of the Court: William J. Brennan → go there Dissenting: Rehnquist. Applied: the Fourteenth Amendment → go there Topic: Immunity from civil rights violations. Monell v. Department of Social Services, 436 U.S. 658 (1978), is an opinion given by the United States Supreme Court in which the Court overruled Monroe v. Pape by holding that a local government is a "person" subject to suit under Section 1983 of Title 42 of the United States Code: Civil action for deprivation of rights. Additionally, the Court held that §1983 claims against municipal entities must be based on implementation of a policy or custom. Wiki link