But not for much of the drug prisoner population. I think there are something like 40,000 pot prisoners out of about 500,000 drug war prisoners.
A disproportionate number of those drug war prisoners are poor people of color. Funny how that works.
Retaining the prohibition on hard drugs retains all the harms associated with prohibition: Law enforcement corruption, retail and wholesale illegal drug business (gangs and cartels) violence, black market prices leading to acquisitive crime, all the downsides of using law enforcement to solve social problems. And there will still be hard drugs easily available. That's how it's been so far.
I favor ending drug prohibition, period, and dealing with drugs as a public health issue, not a criminal one. We can talk about how that might work, if you like, but a kind of cold way of thinking about it is to say we should treat drugs like alcohol and leave the cops out of it except to clean up the mess.
With alcohol, law enforcement involvement is limited to people who threaten the public safety (drunk drivers), the public order (public intoxication--in some places, disturbing the public), or who are committing crimes under the influence (bar fights, domestic aassaults, child abuse or neglect, other stupid, drunken shit). We don't arrest alcohol users and we don't go after "alcohol trafficking organizations."
We suffer some social harms from alcohol, but we've removed the harms caused by prohibition. I think you could reasonably argue that not prohibiting alcohol is a net harm reduction. We could do that with other drugs, too, especially if coupled with access to treatment on demand under a sane health care system.