the legal fiction is that the Controlled Substances Act relies on the Interstate Commerce Clause to apply - Congress can only ban drugs on Federal land, and ban

the legal fiction is that the Controlled Substances Act relies on the Interstate Commerce Clause to apply - Congress can only ban drugs on Federal land, and ban drugs as part of its power to regulate interstate commerce in drugs. Congress doesn't have arbitrary power over states (in theory!) so states would argue that since pot is only legalized within their borders, and isn't (legally) sold across state lines, the CSA doesn't apply. the Federal government would disagree, and would probably win in a fight citing Wickard v. Filburne or that machine gun case, but they couldn't force states to actually enforce their drug laws - it'd be a battle of attrition with the DEA, and it'd piss the states off. honestly, I think they decided it wasn't worth the fight since pot is pretty popular, so they let sleeping dogs lie.