OK, look at it this way. People putting whatever they want into their body results in a huge drain on society in both costs and lost productivity. That includes various cancers caused by tobacco, health hazards of alcohol including lost lives from car wrecks, etc, as well as the many lost lives from drugs. It isn't just about what the individual wants to do to themselves but also the harm caused to themselves, to others, to society in general. Don't forget all the crime committed to get the money to obtain drugs, which will still go on prohibition or not. You make individual liberty paramount, but individual responsibility should be as important, and drug abusers aren't being responsible, so it's up to the government to try to mitigate the damage done to society. It isn't prohibition that's the bad guy, it's the abuse of substances that shouldn't be touched and their affect on the abuser and everyone else.