I agree with post 5. Somehow I think that fully legalizing marijuana would open up a pandora's box of problems that we may not (or could not) have planned for.
On the other hand, as an illegal drug, I often question the argument that marijuana is more unsafe than many prescription drugs that are completely legal. I think of the number of fraudulent vicoden, hydrocodone, and oxycodone prescriptions that are reported as written, and how many people are said to be "addicted" to pain-killers. I know what the side effects of vicoden are on me, and they seem as unhealthy (arguably worse, even) than the side effects of marijuana. I wish there was a way bring more scholarly research to light on the potentially positive medical effects of marijuana when used under supervision. 16 states and Washington DC already support it.