"Legalize it and tax it" has been the mantra, with the taxes earmarked to fund treatment. The latter will never happen, because government cannot help itself from spending whatever money it can on whatever it thinks will buy votes.
And there will still be a market for black market drugs. The legal, high-quality, taxed drugs will be more expensive than the underground variants. People will still make and sell homebrew meth, just as people still make and sell homebrew booze.
This isn't to say that I think we should keep things the way they are. There are many intoxicating substances that cause grievious harm to individuals, families, and society in general and I don't think that any of the illegal ones are worse than alcohol in that regard. And I don't think that getting high or being addicted is a criminal act (though it may lead to things that are criminal, such as stealing, driving under the influence, etc.)
I also think that intoxicating oneself is usually a bad idea, particularly if it's done to escape from or avoid some problem or life situation that needs to be dealt with and resolved. My worry is that legalization will be percieved as endorsement, absent any campaign to highlight the ethical, moral and personal responsibility expectations that people will need to live up to. And we seem as a society to have really gotten shy about teaching that certain behaviors and ways of living can be right or wrong, absolutely.
