Over at Overcoming Bias, and argument for exile as a means of reducing the costs of our prison system.
I think, though, that it’s important that our prison system not become too inexpensive. The marginal costs of incarceration should be sufficiently high as to create a disincentive for the state to imprison people with impunity. (In particular, I think it should be high enough to get the government to reconsider whether or not it is effective, both from direct and societal costs, to imprison non-violent drug offenders.)
An interesting thought to consider: should we be incarcerating people convicted of non-violent crimes? Is the purpose of prison simply to keep dangerous people away from society as a whole, or is it also a means of discouraging crime? Or is imprisonment also a form of moral retribution? In which case, should the government be in the business of retribution, and, if so, is the death penalty a legitimate form of retribution?