Combined state and federal incarceration in 2012: 47.7% violent, 52.3% non violent, of which 20.5% is drug related.[1] See also that 20% of 1.5 million is 300,000 people, a lot.

Imagine for a moment a community where 50% of men over 18 are or have been in prison. If you erase 20% of that number then you have a community with a 10% bump in its productive male population. I would imagine that boost in available parents would keep some of those young men from ever slipping into cyclical violence.

[1]http://felonvoting.procon.org/view.resource.php?resourceID=0...