The State can't nullify a federal law as federal law is supreme under the Constitution. However, the federal government may not require the cooperation of state officials in enforcing federal law. So, if the state law simply said "we won't cooperate, do it yourself" that would be perfectly within the state's perogative. See, e.g., Printz, 521 U.S., at 933, 117 S.Ct. 2365 (striking down federal legislation compelling state law enforcement officers to perform federally mandated background checks on handgun purchasers); New York, 505 U.S at 174–175, 112 S.Ct. 2408 (invalidating provisions of an Act that would compel a State to either take title to nuclear waste or enact particular state waste regulations). It has also led us to scrutinize Spending Clause legislation to ensure that Congress is not using financial inducements to exert a “power akin to undue influence.” Steward Machine Co. v. Davis, 301 U.S. 548, 590, 57 S.Ct. 883, 81 L.Ed. 1279 (1937).