In my family there's a story about some relatives who lived in a village near Ypres. Their living room had a big iron stove. When the Germans invaded they they hid some jewelry in a hole under that stove, and fled like everybody else.
After the war they returned to the village, wanting to retrieve the jewels. Not only were they unable to locate the stove, or the house. They were unable to locate where the street had been.
What these sort of tests always ignore is that placebo effect really works. I refer to a recent study by the University of Manchester in which people who believed that they had better hearing aids objectively scored better on hearing tests. If you spend time and money on a nice high-end system, the love that you put into your setup will be returned to you as better hearing experience.
The difference between decriminalization and legalizing trade is significant. In Portugal drug traffickers need to spend energy just to avoid getting caught. A legal cannabis industry on the other hand will have free reign to spend vast resources on lobbying, marketing and making their product as addictive as possible, which may lead to a significant increase of use.
Growing or selling cannabis is illegal in Portugal. Owning cannabis seeds is illegal in Portugal. The only thing that was changed is that the consumer of cannabis is no longer treated as a criminal. I've yet to see a good argument why the same approach wouldn't work in the US.
> The only thing that was changed is that the consumer of cannabis is no longer treated as a criminal.
Right, which is why I say it's going in the right direction. I think full legalization will provide the most benefits to society, but decriminalization of use is a good start.