Christie v. NCAA is a U.S. Supreme Court (SCOTUS) challenge to the federal law that bans states from allowing sports gambling. Though nothing in Christie addresses cannabis directly, SCOTUS’s decision, due out next year, could give Congress a tool to ban states from allowing legal marijuana. In 1992, Congress passed the Professional and Amateur Sports Protection Act (PASPA), which prohibits states (save for some that were grandfathered) to “authorize” gambling on sports. The state of New Jersey, which was not grandfathered, passed laws in 2012 to authorize sports betting. In a federal case, the state admitted that these laws violated PASPA, but argued that PASPA unconstitutionally allowed the federal government to “commandeer” the state to enforce federal law. The Court of Appeals found that the Constitution’s anti-commandeering doctrine (derived from the 10thAmendment) didn’t apply here because PASPA didn’t affirmatively require New Jersey to do anything, but simply prohibited it from enacting laws that allowed betting on sports. The Supreme Court declined to review the Court of Appeals’ decision. In 2014, New Jersey passed a new law that merely repealed existing its laws prohibiting sports betting. The Court of Appeals was unconvinced that the new law was any different than the 2012 law. According to the Court of Appeals, the difference between “authorizing” sports gambling and “repealing” laws that prohibited sports gambling was insignificant. The result in either case was that New Jersey allowed gamblers in New Jersey to bet on sports, which was banned by PASPA. This time SCOTUS took notice and agreed to hear the case. New Jersey’s brief before SCOTUS argues that under the anti-commandeering doctrine, it makes no difference whether the federal law prevents a state from repealing a law or affirmatively forces it to pass a new law. Either way, the federal government is forcing New Jersey to regulate conduct that its voters would rather leave unregulated. At least one amicus curiae brief argued that upholding the lower court’s decision would allow Congress to require states to affirmatively ban medicinal or recreational cannabis, denying the states their traditional role as experimenters in parallel legal regimes. On December 4, 2017, SCOTUS heard oral argument in Christie v. NCAA. While it is difficult to predict the final decision simply from oral arguments, at least one noted commentator opined that “Justices seem to side with the state on sports betting.” But what will happen to state-legalized cannabis if SCOTUS goes the other way and upholds the lower court’s decision? Nothing at first. Christie will only decide the question of whether the lower court properly found that PASPA applies to the New Jersey law. Although Justice Sotomajor mentioned marijuana in passing at oral argument, the issue of state marijuana regulations is not before SCOTUS in Christie. In the future, however, it is at least conceivable that Congress could take its lead from such a ruling and pass a law that requires states to repeal their legal cannabis regulations.