In the most enlightened society, there would be no prisons because there would be no crime. Obviously, we have a long way to go before that is true. But one of the ways we can commit to the path towards that reality is to shift our consciousness around prisons in particular and in criminal justice in general. Faith in God's grace means faith in people's capacity to change, and thus to be rehabilitated. We can't believe in a redeemed America if we don't believe in redemption.
Prison can have an atonement value for some people, and certain criminals clearly belong there.
Prison obviously still has a real function. But the consciousness around prisons in America today is laden with a consciousness of guilt and punishment, with far too little emphasis on the genuine rehabilitation of people's lives. Most violent crime in America is committed by people who have already served time in jail. In Texas, when Ann Richards was governor, she introduced drug and alcohol rehabilitation programs into the Texas prison system. The rate of recidivism during her tenure dropped, in some cases, dramatically.