Justice Alito’s majority opinion in Murphy v. NCAA purports to faithfully apply Printz v. United States. But it doesn’t. Part III.C of Justice Scalia’s majority opinion in Printz explains that the textual basis of the commandeering doctrine is the Necessary and Proper Clause:

The dissent of course resorts to the last, best hope of those who defend ultra vires congressional action, the Necessary and Proper Clause. It reasons, post, at 941, that the power to regulate the sale of handguns under the Commerce Clause, coupled with the power to “make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers,” Art. I, § 8, conclusively establishes the Brady Act’s constitutional validity, because the Tenth Amendment imposes no limitations on the exercise of delegated powers but merely prohibits the exercise of powers “not delegated to the United States.” What destroys the dissent’s Necessary and Proper Clause argument, however, is not the Tenth Amendment but the Necessary and Proper Clause itself.

Yet, the Necessary and Proper clause is mentioned nowhere in Justice Alito’s majority opinion. The Court invalidates PASPA without considering “the last, best hope of those who defend ultra vires congressional action.”

Justice Thomas’s concurring opinion provides the correct framework: first, ask if PASPA is authorized by a specific enumerated power, and if not, second, ask if PASPA is authorized by the Necessary and Proper Clause:

I agree with the Court that the Professional and Amateur Sports Protection Act (PASPA) exceeds Congress’ Article I authority to the extent it prohibits New Jersey from “authoriz[ing]” or “licens[ing]” sports gambling, Unlike the dissent, I do “doubt” that Congress can prohibit sports gambling that does not cross state lines. Post (opinion of GINSBURG, J.); see License Tax Cases (1867) (holding that Congress has “no power” to regulate “the internal commerce or domestic trade of the States,” including the intrastate sale of lottery tickets); United States v. Lopez (1995) (THOMAS, J., concurring) (documenting why the Commerce Clause does not permit Congress to regulate purely local activities that have a substantial effect on interstate commerce). But even assuming the Commerce Clause allows Congress to prohibit intrastate sports gambling “directly,” it “does not authorize Congress to regulate state governments’ regulation of interstate commerce.” New York v. United States (1992). The Necessary and Proper Clause does not give Congress this power either, as a law is not “proper” if it “subvert[s] basic principles of federalism and dual sovereignty.” Gonzales v. Raich (2005) (THOMAS, J., dissenting). Commandeering the States, as PASPA does, subverts those principles. See Printz v. United States (1997).

Why does the majority opinion not mention the Necessary and Proper clause? Mike Dorf hinted at one possible explanation: Justice Breyer, who dissented in Printz, may have been unwilling to go along with this aspect of Printz. As a result, the Court’s opinion, which said nothing about the Necessary and Proper Clause, managed to invalidate PAPSA without enhancing a doctrine that could be used to invalidate other federal laws.