I think that the separation of church and state is an illusion to begin with, and also that this is one of the major reasons that certain psychoactive drugs are now illegal.

Though our government poses as a republic, it ultimately adopts the monarchical religious view that there is one god who is 'ruler' of the universe. Thus, many illegal drugs which lead to mystical experiences, namely cannabis, psilocybin, and LSD, are deemed dangerous because such mystical experiences are direct threats to the religious traditions of the church. If someone living in our western society suddenly claims equality with, or worse, identifies himself or herself as 'God', they are viewed as insubordinate and labeled as blasphemous or insane, while such beliefs are not at all uncomon in many eastern and native American religions.