As a country and individual localities, we spend massive amounts, despite deficits, to prosecute people, allegedly to protect them from themselves.
If there is no victim for a crime, the "criminal" becomes the victim of the law.
This does NOT mean that dangerous uses like driving under the influence should be allowable.
Education is the only answer for drug problems, prohibition only helps criminals... Self medication or even self-destructive recreation (not to even imply acceptance that marijuana is actually destructive) should be a person's own educated choice.
If we cannot stop empowering organized crime and use this substance as a tax (and job) source, we can, at least, stop spending so much on enforcement and imprisonment for its use, and drive down its value to criminals.