If you look at more than just the current incarceration rate and look at the chance of an American man having spent time in prison you’ll find even more horrifying statistics.  From http://www.csmonitor.com/2003/0818/p02s01-usju.html:

If current trends continue, it means that a black male in the United States would have about a 1 in 3 chance of going to prison during his lifetime. For a Hispanic male, it’s 1 in 6; for a white male, 1 in 17.

Those numbers seem to be more conservative than ones I’ve seen during my days debating where I’d see statistics that said half of black men have been to prison and 1 in 7 males.  Here’s something partially corroborate those numbers from: http://www.nytimes.com/2006/03/20/national/20blackmen.html

Incarceration rates climbed in the 1990’s and reached historic highs in the past few years. In 1995, 16 percent of black men in their 20’s who did not attend college were in jail or prison; by 2004, 21 percent were incarcerated. By their mid-30’s, 6 in 10 black men who had dropped out of school had spent time in prison. In the inner cities, more than half of all black men do not finish high school.

How do you like those numbers, guys?  How do you like the feeling of living in a country where you have a good chance of spending time in prison?  How do you like the feeling of knowing that virtually everywhere you go you are around people who have been affected by a prison experience?  And, prison isn’t pretty.  You have a pretty good chance of getting sick.  From: http://hab.hrsa.gov/tools/openingdoors/

In the United States, 20 to 26 percent of people living with HIV/AIDS (PLWHA), 29 to 43 percent of those infected with the hepatitis C virus, and 40 percent of those who have TB passed through correctional facilities during 1997.

Prison is a cesspool of disease where any skills, money, dignity and resources a prisoner might have are quickly erroded by a environment which doesn’t prepare you for the outside world.  That would explain the recidivism rates.