I posted this somewhere else but it's even more applicable to this topic.
This shows the incredulity that the UK views America when it comes to incarceration.
http://www.youtube.com/watch?v=nPZed8af9RI
In the UK we had a political phrase "Tough on crime, tough on the causes of crime". In the US it seems that they are only doing the former - spend money on being tough but do nothing or less than nothing to address the causes of crime, social issues etc.
And of course, they make money from prisoners ... someone is getting rich. It's the slave-trade re-invented ...
The approach doesn't appear to work for the purpose it's portrayed - the US appears to have a very violent society. But it is very effective at providing cheap labor for someone to make money off so I guess to them it's working just fine thank you very much.