Flippity-floppity.

If watching Bush flip-flop over the course of a few hours isn't convincing enough, then you can watch Bush flip-flop in a debate with himself, courtesy of The Daily Show and Alex Cohen's great website of clips. The clip is a parody of Bush from 2003 shwoing George W. Bush the President against himself as Governor of Texas. It's a no-brainer in every sense. Principled politics in action.