Beck: Watch This Film
From Billy Beck:
"The History of Political Correctness" -- twenty-two minutes at Google Video.
This traces the Marxist history of what's commonly known as "political correctness", which is a species of Marxist class consciousness. Everything I saw in it comports with my own general reading on the matter for decades.
Understand: the ethical and political Balkanization of America is a sort of giant dice-roll through history to see which power-pressure-group could come up snake-eyes as the bearer of the failed revolution.