Sorry but I don't think that the size or demographics of Portugal vs. the USA matters, the point is, their drug abuse has dropped by half. Or are you suggesting that North Americans are too stupid to take advantage of the help that Portugal offers their users instead of just throwing them in jail?
Alcohol causes more problems that smoking pot does and alcohol is addictive whereas pot isn't. I've even read a study by an insurance corporation in the US where they found that after study the stats, pot actually seems to be the cause of fewer accidents as those folks tend to drive slower and more cautiously whereas alcohol gives people the feeling that they are invincible and more often speed and drive recklessly.
http://www.prweb.com/releases/prweb2012/4/prweb9375729.htm?PID=6149635
And this article printed in Scientific American shows that pot smoking has no impact on cancer rates despite it having higher deposits in the lungs. The use of marijuana doesn't seem to be the problem that nay-sayers declare it is, at all.
http://www.scientificamerican.com/article/large-study-finds-no-link/ In fact, it's surmised that the THC in the pot actually kills the aging cells in the lungs before they become cancerous.
I even found an article in the Washington Post that says that traffic accidents have actually decreased in Colorado since they legalized the use of pot.
http://www.washingtonpost.com/news/...lities-in-colorado-are-at-near-historic-lows/