What does legalization change? People who are at the screwed end of society will continue to be so in either world. People at the top will continue to be at the top. The only change is the tax status I think.
It changes people going to prison for good chunks of their life for something like smoking a joint, which is arguably much less harmful than alcohol and cigarettes. It is better to get people help than toss them in prison. However there are still arguments against full legalization:
To answer that, one may try to research the history of prohibition in the USA and the effects of legalizing alcohol after that period. I would suspect a strong correlation.
Keeping the drugs illegal helps the criminal operatives and corrupt officials stay in control of the distribution.
