I'm sure Phil will be writing something for the Chronicle about this, but in the meanwhile, I wanted to post a quote from the article by Mike Males, the researcher who authored the study:
"The War on Drugs is not intended to solve the drug problem -- it's intended to maximize the harm drugs cause in society."
I strongly agree with this and I think it sums up one key aspect of our prohibitionist policy. It's not that most supporters of the drug war think this consciously. It's that the drug war support is incoherent and emotionally based. Drugs have to continue to harm people, and more than they might do on their own without public intervention, so that we can continue to point out how bad drugs are.
If the harm that drugs do can be reduced -- and the harm of drug policies of course counts as harm from drugs, that's how incoherent it is -- there would be less reason for people to refrain from drug use, and less opportunity to tell people not to use drugs or to say we told you so. Given how low marijuana falls on the harmful substances scale, it's especially important for zealots to focus on marijuana. Otherwise people might get the idea that it would be okay to legalize it. (Oh wait, that's happening anyway...)