It hasn't worked that way since the SCOTUS screwed us in their misbegotten decision in Wickard v. Filburn. The Feds can do whatever they damn well please under the Elastic Clause, and there's not a damned thing the states can do about it.That is not true, not even close. The constitution is still in effect, and it states clearly that unless a law is specifically lined out in the constitution through an amendment, then state law takes precedent. It doesn't always work out that way, but that is gist of it.