I agree with Glorb and Suffix. Legalization of drugs works in theory... but that's it. You can prance about all you want, proclaiming that people will have self control and lose interest in mind-numbingly addictive substances the instant they become legal. Seriously?
If anything, it would provide the innocent never-tried-it bystander with even more opportunites to get hooked. All of a sudden, the people who are too poor to afford pot from dealers will be able to get it anywhere, and for cheaper, which increases the potential for other people to be exposed, spreading the virus. People don't do things because it's illegal, they do it because it's fun or they're addicted.
I sincerely hope illegal potent drugs are never legalized. In fact, I hope cigarettes and other tobacco products are made illegal eventually. Sure, it'll probably never happen, but the world would benefit infinitely from it.