Does a city have an obligation to comply with both state and federal law?

Like all other employers, cities must obey the commands of both state and federal law; they are excused from compliance with state or local law only when such compliance would necessarily conflict with the requirements of federal law. Cf. United States v. City of Chicago, 549 F.2d 415, 438 (7th Cir.), cert. denied, 434 U.S. 875, 98 S.Ct. 225, 54 L.Ed.2d 155 (1977). The fact that their previous practices may have met the requirements of state law while violating federal law does not mean that in the future the former may be disregarded. Their duty is to develop a system that meets the requirements of both if such a result is possible. See generally Chance v. Board of Examiners, 561 F.2d 1079 (2d Cir. 1977).