Like Jared Bernstein, I think that part of what flummoxed President Obama in the first debate was the sheer chutzpah of Mitt Romney's claim that he never called for a $5 billion tax cut or $2 billion more for defense. You could see it in Obama's face the first time Romney did that.
Bernstein calls it shape-shifting and notes that Biden managed to stop some of Ryan's doing it, although the only way to do it seems to be to grab the shape-shifter in the act, which in these debate formats means interrupting.
Which somehow reminded me of a song from long ago. Its intent was quite different, but most of the lyrics could be the property of R&R:
Cross-posted to The Agonist.