A much larger proportion of people are in federal prison for drugs than state prisons. (Gut check: there are few federal crimes that people regularly go to prison for, trafficking is one of them).

John Pfaff has done a lot of research into this [1], and drug offenders are a small minority (~20%) of prisoners. The bulk of prisoners are in for violent crimes, which makes the politics of decarceration... tricky.

[1]: https://ir.lawnet.fordham.edu/cgi/viewcontent.cgi?article=16...