What would it cost to ship the criminal element elsewhere and give them enough to live on for about 5 years, en masse?
I'm sure there would be an ROI to calculate. It's why I would agree to spending billions on a HUGE Supermax federal prison out in West Texas. I mean a facility for about 500K inmates with only a heavily guarded and armorred perimeter. Airlift inmates in and nobody leaves, EVER. Let the states purge their own prisons for criminals that can be "reformed" or only have some minor offenses. States could lease the "care" of inmates to the fed. But make sure there are no cameras or media allowed into the interior, EVER. If we don't see it, it didn't happen. I am sure there would never be a problem with over crowding. That would take care of itself. Air drop food and pump in some water. This too would save us money and reduce the crime rate. You could even throw illegals (multiple offenders in there).
It's a fantasy. But just the idea of the place would reduce crime.