CBS released a little 4+ minute preview of Senator John McCain's visit to Late Show with David Letterman (the full interview airs tonight at 11:35 p.m.). McCain cancelled a visit to the show late last month, telling Letterman he had to get back to Washington D.C. to deal with the economic crisis...but actually stuck around for interviews with other outlets, prompting Letterman's relentless skepticism.

In the clip above, McCain admits he "screwed up". Letterman asked some tough questions too, about William Ayers, how Sarah Palin talks about Obama "palling around with terrorists" (plural--so who ar the other terrorists), and questioning McCain's relationship with G. Gordon Liddy! Maybe Letterman should have been one of the debate moderators.