Of course, there are some terrible people in prison that warrant severe punishment. However sixty percent of the inmate population are there for nonviolent offenses; one-fourth of the inmate population are there for nonviolent drug offenses. Ignoring whether sending nonviolent criminals into this environment is moral, the natural response is that severe punishment is a deterrent to crime. However, the literature overwhelmingly supports certainty of punishment as a far more effective deterrent than severity of punishment.
During this time of budget austerity pressures, people are finally noticing that incarcerating inmates is expensive. In a state like California it annually costs $47,000 per inmate. The average across states is a little more than $32,000. Note that these are accounting costs that fail to capture lost work opportunities and time away from parenting and loved ones.
Naturally, we should support the Attorney General as he recommends lowering sentences for nonviolent drug offenders. More broadly, we should consider whether it makes sense for us to pursue the expensive yet less effective strategy of incarcerating nonviolent inmates in inhumane environments for lengthy periods of time.