I would like to see the stats with people who are in prison for low level drug offenses taken out. I suspect the numbers would start to be much closer to the European numbers.

I personal theory is that there are two types of criminals - normal people who do the occasionally stupid thing (stealing a single item from retail or getting into a bar fight), and people who make crime their career path. The US model is to treat everybody as being in the latter group, while the Scandinavian model is to treat everybody as being in the first group. Instead we should treat people based on who they are, even if that means very different sentences for the same crime to different people.