End the war on drugs and retain criminalization - in other words, if you use it and make a nuisance of yourself, expect jail. But no random searches, no raids, no property seizures, no spending billions of dollars in corrupt third-world nations on the drug war.
The important issue is not the drugs, it is the expansion of government power. Sure, get rid of the welfare state that would in effect subsidize drug abuse (Medicaid, etc) if drugs were decriminalized, and then we can talk about decriminalization. But for now, the socialists have forced society into directly paying through taxes for the poor choices of individuals. We cannot have both freedom from personal responsibility (socialism, the welfare state) and unfettered liberties. Crush the socialism, crush the welfare-state, and it will be much harder to justify the police and the nanny-state.
That’s a pretty good argument, but not so much for marijuana. Marijuana isn’t harmless, but it’s not particularly debilitating to the vast majority of people who smoke it. According to government survey results, in the neighborhood of a 100 million people in this country have smoked marijuana. And the government numbers are probably low because there will always be some percentage of folks not willing to admit illegal conduct to government workers who come to their homes. Most who smoke marijuana only do it some when they are young and then they grow out of their wild youthfulness and leave it alone. Some continue to smoke, but really only a very tiny percentage of those who smoke it are actually debilitated to the point that they become a drain on the system. It’s just not a particularly addictive or debilitating drug. Most smoke a little after work, on weekends or whatever, or even just on special occasions, no different than the way people drink alcohol. And its effects really don’t tend to be as debilitating as alcohol. Too much of either are bad for the user and those around him, but again the vast majority aren’t just going crazy on the stuff. According to the government numbers the vast majority who admit use are full time employed. They’re regular working Americans who happen to enjoy smoking a little weed. Your argument works for a drug like heroin or some other drugs that turns most regular users into burdens on society, but it falls flat when it comes to marijuana.