There should be no one in prison that is a non-violent offender. Most of non-violent offenders are related to drug use. Put them in a rehabilitation center and teach them that kind of life is wrong. Teach them a skill and get them a job when they graduate the rehabilitation program. It would save a lot of grief and money in the long run.
Our traumatized world perpetuates its trauma. The only way forward is to realize that criminals often come from abusive or impoverished backgrounds. It's not that they haven't done wrong, but they have also often been failed by their families and their larger community. Reform is not an easy task, but it must be embraced, not simply within the walls of prison, but in the wider community as well, which, for example, creates abusive police officers and drug trafficking CIA agents.
I think the majority of criminal sentencing should focus on rehabilitation, even though I think this, too, is an exercise in futility in most cases. There are very rare cases where criminal sentencing should absolutely be punishment. For example, if you commit a heinous murder or rape, you do not deserve rehabilitation.
I believe criminal sentencing should focus on rehabilitation, but I also believe criminals need real second chances rather than the situation they are handed today. After a criminal is released their record continues to follow them, which makes it more difficult to obtain employment. If we can't give them the appropriate chances there's no point in rehabilitating.
I think that criminal sentencing should focus on punishment, rather than rehabilitation, because so many criminals do not want help. The success rate for treatment is small when the people want to be in treatment. When the treatment is forced, the success rate is even lower. We should just punish crime and leave them to their own choices.