Obama was unprepared for Mitt's lying.

So says Chait.

Romney won the debate in no small part because he adopted a policy of simply lying about his policies. Probably the best way to understand Obama’s listless performance is that he was prepared to debate the claims Romney has been making for the entire campaign, and Romney switched up and started making different and utterly bogus ones. Obama, perhaps, was not prepared for that, and he certainly didn’t think quickly enough on his feet to adjust to it.

Uh, this is a weak excuse, if true. Romney's done nothing but Etch-a-Sketch and lie throughout the entire campaign, so not being prepared for Romney's lying seems inexcusable.