If it is beyond the power of government to make neighborhoods safe for people who do not harm others, how is it that you came up with a notion that it is even possible to make life safe for violent people (many of whom should justly have been executed) to be safe while incarcerated together?
There's that word "together". If we give the little thugs very small private cells, with solitary confinement 23 hours a day, and stagger their hour out so that we let fewer of them out at any one time, they should be much safer. They will be alone and therefore safe most of the time. When out, there will be fewer to watch, and we can keep them safe. They may be miserable being alone so much, but I'm okay with that.