Stated Justice O’Connor for the Court in New York v. United States, 505 US 144 (1992):
“While Congress has substantial powers to govern the Nation directly, including in areas of intimate concern to the States, the Constitution has never been understood to confer upon Congress the ability to require the States to govern according to Congress’ instructions. See Coyle v. Oklahoma, 221 U.S. 559, 565 (1911). The Court has been explicit about this distinction. “Both the States and the United States existed before the Constitution. The people, through that instrument, established a more perfect union by substituting a national government, acting, with ample power, directly upon the citizens, instead of the Confederate government, which acted with powers, greatly restricted, only upon the States.” Lane County v. Oregon, 7 Wall., at 76 (emphasis added)...”
...”In providing for a stronger central government, therefore, the Framers explicitly chose a Constitution that confers upon Congress the power to regulate individuals, not States. As we have seen, the Court has consistently respected this choice. We have always understood that even where Congress has the authority under the Constitution to pass laws requiring or prohibiting certain acts, it lacks the power directly to compel the States to require or prohibit those acts. E. g., FERC v. Mississippi, 456 U. S., at 762-766; Hodel v. Virginia Surface Mining & Reclamation Assn., Inc., 452 U. S., at 288-289; Lane County v. Oregon, 7 Wall., at 76. The allocation of power contained in the Commerce Clause, for example, authorizes Congress to regulate interstate commerce directly; it does not authorize Congress to regulate state governments’ regulation of interstate commerce.”
In Printz v. United States and Mack v. United States, (June 27, 1997), Judge Scalia for the Court stated:
...”Finally, and most conclusively in the present litigation, we turn to the prior jurisprudence of this Court. Federal commandeering of state governments is such a novel phenomenon that this Court’s first experience with it did not occur until the 1970’s, when the Environmental Protection Agency promulgated regulations requiring States to prescribe auto emissions testing, monitoring and retrofit programs, and to designate preferential bus and carpool lanes. The Courts of Appeals for the Fourth and Ninth Circuits invalidated the regulations on statutory grounds in order to avoid what they perceived to be grave constitutional issues, see Maryland v. EPA, 530 F. 2d 215, 226 (CA4 1975); Brown v. EPA, 521 F. 2d 827, 838–842 (CA9 1975); and the District of Columbia Circuit invalidated the regulations on both constitutional and statutory grounds, see District of Columbia v. Train, 521 F. 2d 971, 994 (CADC 1975). After we granted certiorari to review the statutory and constitutional validity of the regulations, the Government declined even to defend them, and instead rescinded some and conceded the invalidity of those that remained, leading us to vacate the opinions below and remand for consideration of mootness. EPA v. Brown, 431 U. S. 99 (1977).
“Although we had no occasion to pass upon the subject in Brown, later opinions of ours have made clear that the Federal Government may not compel the States to implement, by legislation or executive action, federal regulatory programs. In Hodel v. Virginia Surface Mining & Reclamation Assn., Inc. 452 U. S. 264 (1981), and FERC v. Mississippi, 456 U. S. 742 (1982), we sustained statutes against constitutional challenge only after assuring ourselves that they did not require the States to enforce federal law. In Hodel we cited the lower court cases in EPA v. Brown, supra, but concluded that the Surface Mining Control and Reclamation Act did not present the problem they raised because it merely made compliance with federal standards a precondition to continued state regulation in an otherwise pre-empted field, Hodel, supra, at 288. In FERC, we construed the most troubling provisions of the Public Utility Regulatory Policies Act of 1978, to contain only the ‘command’ that state agencies ‘consider’ federal standards, and again only as a precondition to continued state regulation of an otherwise pre-empted field. 456 U. S., at 764–765. We warned that ‘this Court never has sanctioned explicitly a federal command to the States to promulgate and enforce laws and regulations,’ id., at 761–762.
“When we were at last confronted squarely with a federal statute that unambiguously required the States to enact or administer a federal regulatory program, our decision should have come as no surprise. At issue in New York v. United States, 505 U. S. 144 (1992), were the so-called ‘take title’ provisions of the Low-Level Radioactive Waste Policy Amendments Act of 1985, which required States either to enact legislation providing for the disposal of radioactive waste generated within their borders, or to take title to, and possession of the waste—effectively requiring the States either to legislate pursuant to Congress’s directions, or to implement an administrative solution. Id., at 175–176. We concluded that Congress could constitutionally require the States to do neither. Id., at 176. ‘The Federal Government,’ we held, ‘may not compel the States to enact or administer a federal regulatory program.’ Id., at 188.