I think he was referring to the lost "war on drugs" that the US has been fighting for decades now, not that I would expect you to read this reply or understand it if you did.

Regardless of whether legalization of marijuana (or any other drug) would be good for the economy, I support people's freedom to ingest whatever chemicals they wish to--with restrictions like alcohol has.  I most definitely see the drawbacks of substance use/abuse, but the crime that has been manufactured because of drugs being illegal has harmed society more so than if they were legal.  Anyone seen any of those Mexican cartel torture videos?  That shit is brutal and is a direct result of US drug policies, and Mexico's as well.

As to economic effects, it certainly couldn't hurt.  I have a hard time believing the gain in tax revenue and jobs associated with the marijuana industry would be undone by its harm to health or society.  I think a lot of people have known that for a long time, but trying to get a government to change its idiotic ways is very difficult.