There are 10th amendment arguments in San Diego v Norml et al which will uphold the anti commandeering doctrine.This is what I use to make the argument that the state,county and city volenteer to uphold a federal drug control strategy.They can't be ordered to.

State,county or city cant be ordered to enforce federal regulatory schemes.
Feds can't regulate medical practice.Nothing left for the state to do except go against the will of the people...for a fee...or grant in this case.