To act as the devils advocate I do have to note that Norway has less social problems than the US in general which also affects the level of crime, e.g. you have no minorities recently out of slavery and not much immigration (Sweden and Denmark have way more immigration though but still have quite little crime).

I am a firm believer in the Norwegian style of punishment and rehabilitation. The goal of a justice system is not to punish or get revenge but to create a safe society with little crime, and if rehabilitation does that (which is what I believe) then we should have more rehabilitation.