The Professional and Amateur Sports Protection Act (PASPA), which Congress passed in 1992, forbids states from “authorizing” sports betting “by law.” As every middle-schooler learns, however, our Constitution establishes dual sovereignty between the states and the federal government. And as the Supreme Court most recently held in New York v. United States (1992) and Printz v. United States (1997), the Constitution forbids Congress from “commandeering” state officials to serve federal ends, whether by forcing states to enforce federal laws or to pass new state laws (or to refrain from repealing old ones), which is exactly what PASPA does. In 2011,...