"Does the criminal law do more good than harm?" is a straw-man question. To think that answering NO condemns our criminal law is a fallacy of distribution. (a cool phrase I found in one of the readings.)
YES, I agree that we do more harm to the people we incapacitate than we prevent to their potential victims.
However, over-incarceration only indicates a hysteric willingness to punish (relatively) victimless crimes -- i.e. utilitarianism with the thumb on the scale of white-collar comfort. It CANNOT logically tell us that we have underutilized softer options with better utilitarian outcomes.
The criminal law does LOTS of harm, because it's the last tool we have. We reserve incarceration for cases that were least responsive to the rest of the system. It is the last and most drastic of a series of processes designed to effect the goals (esp. utilitarianism) of a whole swath of crime-related law. This complex includes elementary schools, churches, special-ed programs, unemployment insurance, sex-ed classes, Sesame Street, civil courts as fora for disputes, and criminal sanctions. In a legal system seen functionally, all these have criminal implications. (I guess they're also all Criminal Law, since Sesame Street is on PBS.)
"Could we better distribute potential perpetrators among this system?" Perhaps we SHOULD shift harms dealt with ex-post by the criminal code into the preventive, social code. We have made huge advances in psychology and education.
But it may happen that the optimum distribution of cases within this complex does not optimize each individual system. That's Cohen's fallacy of distribution. The criminal justice system is SUPPOSED to look shitty, because it catches the failures from every other system in the complex.

-- AndrewGradman - 25 Jan 2008

Andrew: My understanding of your comment above is that:

(1) The criminal justice system catches those who fall through the cracks of the other institutions designed to make society run smoothly.

(2) Since it is populated, inherently, by those who couldn't pull it off given those other opportunities, it must look terrible.

(3) The terrible nature of the criminal justice system - therefore - cannot tell us that those other systems in society were broken.

I am not 100% sure what "utilitarian" means. I looked it up, but you will have to forgive me for my crude understanding. However, I think it is pretty clear that with one in every 31 American adults tied to the criminal justice system (incarceration, parole, probation) at a cost of over $60,000,000,000/year (not including new prison construction which is projected to be an additional $5 or $6 billion a year) it is quite possible we are losing more by supporting the prison industrial complex than we could ever gain in “white collar comfort.” There are certainly better ways to spend our money and the best evidence is just how broken those other systems (except possibly Sesame Street) you mentioned are.

If our schools are designed to keep our children out of the criminal justice system and your average high school in a poor community has a lower than 50% graduation rate, you have a broken safety net. If our sex-ed classes are supposed to prevent teenage pregnancy, but all we have is a gym teacher telling folks to abstain, of course young children are going to be having children of their own. My point is that, one reason our criminal justice system is so overburdened is because the very safety nets you mentioned doesn’t work. And, as a former teacher in urban schools and a product of public schools myself, I can assure you that it is not the “bad kids” that slip through cracks; it is most of the best kids.

A more cynical person might say this is part of the design to maintain an underclass and feed politicians who are “tough on crime,” developers who provide the prisons, and a society that seems to prefer the poor in prison. If utility comes into play at all, the assessment is being done at the very top, by those who gain security and wealth from maintaining the status quo. If it was being done by your or me (or perhaps the people in the communities most effected by incarceration), I am sure our criminal justice system would look a lot different.

-- AdamCarlis - 25 Jan 2008