Right! Although, the precise holding in this case actually gets at the opposite (more unusual) situation. It has already been established that the federal gove

Right! Although, the precise holding in this case actually gets at the opposite (more unusual) situation. It has already been established that the federal government can't compel states to enact laws or enforce federal ones. [1] (The "federal" drinking age is OK because, IIRC, it was not actually done through direct compulsion, but by conditioning the grant of federal highway funds.) The interesting thing in this case is that the Court has also concluded that the federal government can't forbid a state from enacting a law. Of course, the federal government can still enact its own laws (subject to the Constitution's usual limits on federal power), which would preempt state law. This was a weird case where the federal government tried to do the former but not the latter. [1] For example, https://en.wikipedia.org/wiki/Printz_v._United_States https://en.wikipedia.org/wiki/Printz_v._United_States