You don't know how to measure success. We still have murders even though we've been having a "war on murder" since before the nation started.
The current war on drugs keeps the numbers tamped down. If you want to completely eliminate drugs, we will have to start killing drug dealers every time we catch them.
Till we decide to get serious about killing drug dealers, don't talk to me about the success of this one hand tied behind our back effort to interdict drugs.
Again, it is just as if not more successful than the war on murder.
BullCrap, it is just as easy and as cheap to buy MJ and other drugs today as it was 30 years ago, hell maybe even easier. Alcohol has been around for several thousand years, hell, Jesus even created it for a wedding. During prohibition, thousands were killed over the sale alcohol, when was the last time you ever heard of anybody being killed over the production of booze. Murder goes way back to Cain and Able, thats a human thing, been around for a while.