I look at it this way. I could smoke pot and I wouldn't go use cocaine or methamphetamine. I could smoke pot and not cause a ruckus. It all comes down to personal responsibility. Legalize it already. Alcohol abuse causes far, far more deadly crimes than pot smoking and alcohol consumption is legal.
There is no logical arguement to banning pot but legalizing alcohol. Alcohol causes more assaults, domestic violence, car accidents, etc than pot smoking ever will. Cigarettes also put a far greater strain on the medical system by causing an innumerable amount of diseases because of all the chemicals in them.