Simple. The same way you end the War on Murder, War on Rape, War on Armed Robbery, etc. Just make it legal. Heck, let's just wipe all criminal laws off the book. This whole "War on Crime" thing just isn't working. After all, we should just trust our fellow citizens to make only good choices, right?
Stupid analogy. The other acts you cited are violent offenses against others, not matters of personal morality. Exactly how far do you believe the state should go in regulating personal morality comrade.
Common Sense break!
-Murder, rape and armed robbery have a doer and a victim.
-Drug use, alcohol use, and cigarette have a user.
Thus, the two categories are not comperable, neither morally nor legally.
Groups of immoral people not "trusting" others to make good choices is a bizarre concept. The other behaviors you cited were those that violated other's rights. Some idiot smoking grass doesn't violate any of your rights.