Will McCain show up for David Letterman?

Senator John McCain, struggling in the polls, is to go on David Letterman's Late Show this Thursday, three weeks after he cancelled at short notice much to the annoyance of the host. McCain's excuse was that he was postponing his campaign to go to Washington to work on the financial crisis. This week, his Late Show booking comes the night after his third and final TV debate with Barack Obama, considered by many observers to be his last chance to turn round Obama's lead.

Letterman was so angry when McCain cancelled on him he spent much of his show haranguing the Republican candidate (see video below) and suggesting "something doesn't smell right". After expressing his admiration for McCain and his sacrifice as a prisoner of war in Vietnam, Letterman said: "When you call up at the last minute and cancel, that's not the John McCain I know."

He suggested that McCain's running mate Sarah Palin should have been prepared to step up and "be ready" - because "the poor guy is getting a little older" - but then reconsidered, saying of Palin's readiness: "Don't get me started".

The question now is - will McCain show up? The host isn't convinced. Addressing his Monday night audience after news of the Thursday booking leaked out, Letterman said: "It is going to be a big week for John McCain. Today and tomorrow he'll be campaigning, Wednesday is the debate, and then, Thursday, he cancels on me again."