>I never said that people ought to be in prison because of drug use.
>And that covers at least half of the people who are in prison in the
>U.S. right now.
This is incorrect. In state facilities the percentage hovers around 20. In federal it's higher and I believe did reach 50% in the past but has gone down. The federal system, with fewer than 200,000 inmates is far smaller than the state, with well over a million in custody.
I think the idea that half of people in prison are there for drug charges stems from the increase in federal drug prosecutions.
http://www.ojp.usdoj.gov/bjs/prisons.htm
http://www.ojp.usdoj.gov/bjs/fed.htm