This case was argued this week before the U.S. Supreme Court. The issue is whether states have the right to allow legal gambling on sporting events.
Usually the doctrine of preemption would apply, meaning that the states have to yield to the federal government, in an area in which the federal government has enacted legislation. The problem here is that the federal government has not undertaken to regulate gambling. All the feds did was dictate, in a 1992 law, that the states were prohibited from enacting any legislation allowing gambling on sporting events (except for Nevada, which was grandfathered in).
What this means is that the concept of federalism is front and center in this case. It will be interesting to see whether the conservative justices, who usually make a big deal out of claiming to be in favor of federalism, and states' rights, will be true to their conservative roots and rule for the states. Stay tuned.