Sports gambling has long had strong opposition. Congress passed the Professional and Amateur Sports Protection Act (PASPA). PASPA’s most important provision makes it “unlawful” for a State or any of its subdivisions “to sponsor, operate, advertise, promote, license, or authorize by law or compact . . . a lottery, sweepstakes, or other betting, gambling, or wagering scheme based . . . on” competitive sporting events. It is also “unlawful” for “a person to sponsor, operate, advertise, or promote” those same gambling schemes but only if this is done “pursuant to the law or compact of a governmental entity.” PASPA does not make sports gambling a federal crime. PASPA allows the Attorney General, as well as professional and amateur sports organizations, to bring civil actions to enjoin violations. A provision in the law gave New Jersey the option of legalizing sports gambling in Atlantic City-provided that it did so within one year of the law’s effective date. Other states such as Nevada had grandfather provisions. New Jersey voters approved an amendment to the State Constitution making it lawful for the legislature to authorize sports gambling, but this was done well after the one year deadline. The major professional sports leagues and the NCAA brought an action in federal court against the New Jersey Governor and other state officials seeking to enjoin the new law on the ground that it violated PASPA. The State argued, among other things, that PASPA unconstitutionally infringed the State’s sovereign authority to end its sports gambling ban. Without an affirmative federal command to do something, the plaintiffs insisted, there can be no claim of commandeering. The District Court found no anticommandeering violation, and a divided panel of the Third Circuit affirmed. The Supreme Court denied certiorari. New Jersey then repealed the provisions of state law prohibiting sports gambling insofar as they concerned the “placement and acceptance of wagers” on sporting events by persons 21 years of age or older at a horseracing track or a casino or gambling house in Atlantic City. The repeal was effective only as to wagers on sporting events not involving a New Jersey college team or a collegiate event taking place in the State. The same plaintiffs promptly commenced a new action in federal court. They won in the District Court, and the en banc appeals court affirmed, finding that the new law, no less than the old one, violated PASPA by “authorizing” sports gambling. The court went on to hold that this prohibition does not contravene the anti-commandeering principle because it “does not command states to take affirmative actions.” The Supreme court granted certiorari.