This could be McCain's Waterloo: not only is he the representative of the incumbent party whose president can't resolve what's rapidly becoming a gigantic mess, McCain himself made a fuss about coming back to Washington last week to help negotiate a bipartisan deal to address the financial crisis. He looks bad, his president looks powerless, and his party looks utterly incompetent.
And of course he'll try to tell you it's really all Barack Obama's fault.