Short version - a lefty professor wrote a paper a couple of years ago saying what Rush said.
He's now trying to distance himself from 'the paper', has removed the paper from the internet, etc.
Read the first article + links at:
http://www.opinionjournal.com/best/(That's Thursday's edition - for anyone reading this on Friday or Saturday go to the above link and hit the 'archive' button to get back to Thursday)
Disclaimer - I, personally think Rush is a blowhard like most extremists right or left. I thought what he said on the ESPN show sucked because I watch football to watch football, not to watch 'left vs. right for in the self appointed crusade to 'save' the moderates of the world - round #328,383'. It is pretty funny reading though - watching this lefty professor try and weazel his way out of the position his paper has put him in.
Enjoy,
Mike/wulfie