In his great Forbes magazine article, author Jacob Sullum lists the contradictions inherent in current marijuana legislation:
“The comparison of alcohol and marijuana presents an obvious challenge to anyone who thinks the government bans drugs because they are unacceptably dangerous. If anything, that rationale suggests marijuana should be legal while alcohol should be banned, rather than the reverse. Judging from this example, the distinctions drawn by our drug laws have little, if anything, to do with what science tells us about the relative hazards of different intoxicants.”
Well worth reading the entire article here.