I may not be following your question raygun, but the 21st amendment was necessary to repeal the 18th, thereby once again making it Constitutional nationally to hit the sauce. It went further with enforcement language supporting the right of the states to carry on with prohibition if they wanted to. What am I missing?
For crying out loud, it would seem that all that's necessary is the Preamble; Congress can do what ever it wants in that regard. The USA could have the world's shortest consitution.
I share your frustration.
It seems that section II of XVIII is a clue; the States are being granted authority conferred under X.
Sweet.
Its good to be the King; wait for the shake.