Originally posted by Omega Vision
I've never really seen anyone with any expertise on the subject effectively defend the prohibitions on marijuana.
Glenn Greenwald had a recent debate against the former Bush drug czar about legalization.
They seemed to talk more about the harder drugs, but the drug czar did make statements where he even lumped alcohol and such into his argument.
Essentially, he was arguing that there is no "reasonable" level of usage, including with alcohol, and that it is immoral to let anyone use because, once you start, it is a literal inevitability that you will have major problems in your life because of your habit.
paraphrasing, sure, but I remember one of his lines was something like "If you come home and drink a glass of alcohol after work, you will eventually become an alcoholic, this is how this stuff works".
There are interesting stats, such as how most nations that have tried some form of decriminalization or legalization are starting to rethink those policies, however, when compared to some of the pro-drug arguments, the cost/benefit analysis does seem to be fully on the side of ending prohibition.
However, as far as I've ever seen, that is the most reasonable and evidence based argument for drug prohibition.
The video is here:
http://www.salon.com/2011/11/15/debating_bushs_drug_czar_on_legalization/singleton/