Without getting into the merits of restorative justice, I actually think the sentencing guidelines are the result of focusing on the offenders rather than abstract legal principles.

The basic purpose of criminal law is to establish norms for behavior. Punishing any given offender or satisfying any given victim is secondary to establishing a norm so 10 other people won't do the same thing. This is a distinct concept from "deterrence." The idea of deterrence is to force people to include the probability-weighted cost of a jail sentence into their cost-benefit analysis. A jail sentence twice as long means a twice as strong deterrent effect. However, given the practical probabilities of getting caught for many crimes, deterrence doesn't really exist. Say 2 years for stealing a bike times a 0.1% chance of getting caught = deterrent effect of 0.73 days in jail per bike. The punishment isn't deterring anyone. What's keeping people from stealing bikes is the social norm created by making bike stealing illegal and punishing offenders.

This rationale for criminal punishment supports having crimes be punished in proportion to how egregious a violation of the social norm has occurred. That's why punishing someone less for stealing food to feed a hungry child is justifiable. Within a restorative justice theory less punishment is appropriate because a small breach of social norms requires less healing, but that only focuses on the singular event. The additional justification is that a small breach of the social norm requires less punishment in order to maintain the norm for everyone else.

At some point in the 1960's, people (mostly liberals) decided that criminal law should be about rehabilitating the offender. This led to a focus on the offender, rather than the offense. Hence three strikes laws, ridiculous sentencing enhancements or reductions for whether an offender seems contrite at sentencing, etc. Ironically, this thought process also led to an inflation of sentences, because people more easily rationalized increasing maximum sentences when those maximums would only be applied to "bad people."

Of course restorative justice isn't coextensive with the 1960's idea of rehabilitative justice, so I'm not saying it suffers from the same problems.

> The basic purpose of criminal law is to establish norms for behavior.

Once you start making assertions like this, you're already into a particular kind of theory of justice. There are a few. It's not really possible to say that there is one true purpose of criminal law.

Now, if you qualified it with our current legal system, it absolutely subscribes to a particular notion of what justice is. And maybe you mean to, without explicitly noting it. But given we're in a discussion about different forms of justice, it would make sense that not everyone agrees with this assertion, and therefore, your others.

  deterrence force[s] people to include the probability-weighted 
  cost of a jail sentence into their cost-benefit analysis.
  ... given the practical probabilities of getting caught 
  for many crimes, deterrence doesn't really exist.

I think the issue is less that the expected value is poor, but rather that most criminals, especially in the cases of crimes we care the _most_ about punishing (murder, fraud, etc), often are not rational.

Even if the punishment were immediate execution a-la Judge Dredd, we would still have people committing crimes, because they irrationally believe that they'll never get caught, or that what they are doing isn't a crime. Or, in some cases, are acting through emotion rather than rationality.

Unless the definition of rehabilitation in the US is different from the rest of the world I don't see any attempts at that. What I have read is increasing "tough of crime" during the decades.

For effective rehabilitation program you need a few things - low sentences for non violent crimes , social norms that not reject the ex felons and allow the reintegration.

Also you need robust job market and social safety network.

And i think that sentencing should be done on scientific grounds and not moral ones.

> Unless the definition of rehabilitation in the US is different from the rest of the world I don't see any attempts at that.

I'm not saying the current system is rehabilitative, but rather that it's a perverse consequence of attempts in the 1960's at making the penal system rehabilitative. The rehabilitative approach shifted the focus from the offense to the offender. This is logical: in a penal system the punishment fits the crime. In a rehabilitative system, the punishment is tailored to the offender (ideally with an eye towards reducing recidivism).

That backfired, because it turns out criminal offenders aren't particularly sympathetic. Once the focus was on the offender, it became much easier for people to justify long sentences and harsh punishment than when the focus was on the crime in the abstract.

The deep irony of the focus on the offender is that it allows us to punish Jamal from the hood much more harshly than Johnny from the suburbs for the same exact crime, all because Johnny doesn't have a rap sheet of minor offenses and is socialized to look contrite and afraid at sentencing.

Rehabilitative law went out of fashion in favor of "neo-liberal" policies in the late 70s/80s which put the focus back on individual responsibility instead of what was viewed as the "welfare" approach to rehabilitation in the 60s.

So I wouldn't call today's policies rehabilitative, they are very much neoliberalist, much like American economic policy.

The idea that criminal law should be about rehabilitation goes back a lot further than the '60s. Look up the etymology and provenance of the word "penitentiary".