Two statements that I think are probably true:
- Putting people in prison minimizes their cultural influence.
- Prison inmates tend to have “regressive” cultural attitudes, at least on some important issues, relative to the general population.
If these statements are true, then it stands to reason that the high rate of imprisonment in the US tends to make our culture more progressive, and that a major reduction in the rate of incarceration would have the opposite effect.
I would, of course, still be in favor of such a reduction, but people who consider themselves progressive should be prepared for the cultural effect of welcoming what amounts to a large migration of people from a rather backward country.