Wow, I'm not used to arguing this side of the drug wars, but I think it's important to make a distinction between different drugs. Bitt makes a valid point that the destructive effects of drugs are not independent of the different communities which abuse them. Mark's point about prior policies along these lines being failures is simply incorrect. When the precursor chemicals to meth are manufactured at precisely nine factories worldwide, regulation can and will have a significant effect in limiting the supply of meth: no input == no output.

Sure, you can make the argument that if every conceivable mind altering substance was entirely legal, that the criminal element would disappear (which appears to have worked with alcohol, but it's less clear that it's worked with gambling). Still, you have to make a public health argument. We took Vioxx off the market because a small number of people had serious complications, despite the large number of people who were happily using it. If the harm caused by the drug (legal or otherwise) outweighs any benefit from having the drug on the market, then you have a legitimate public health policy reason for taking the drug off the market. If you look at meth along these lines, it's clearly something you'd rather not have in the market.

(Fun thought: what company wants to be in the business of manufacturing, marketing, and selling "legal" meth? Who would be willing to take on the liability and lawsuits that would result?)