I only saw the last 20 minutes, so I have no sense of the overall flow. But that was enough to notice:

- Michelle Bachmann, even when given a second chance, seemed genuinely to believe that the federal debt ceiling applied to future spending, not payment for bills and tax cuts the Congress had already voted to enact. Not sure which is worse: that she knows better and decided this was an applause line to push, or she really doesn't know the first thing about the Congressional budgeting process. I bet most Americans also think that holding down the debt ceiling is a forward-looking budgetary step -- ie, that it's like resolving to spend less next month. But they're still wrong. The real comparison is resolving not to pay a credit card bill when it shows up. For a national candidate not to understand this??? Seriously, this is like discovering that your doctor thinks that your trachea is attached to your spleen.*

- Jon Huntsman is really going all-in on the "only reasonable man in the room" strategy, with his gay-rights and debt-ceiling answers. (Not so much about EPA "terrorism.") Hard to see this as a great 2012 plan -- but a brilliant VP move? Or 2016? Also, as Andrew Sprung noted, he has developed a weird shakiness in his speaking voice. (Sprung's hypothesis: "Does Huntsman always sound so trembly? Could it be because he's surrounded by lunatics?") Still, a gutsy strategy on his part.

- This is the best day the beleaguered Barack Obama has had in a while.

- Others better off than they were three hours ago: Perry, Romney (from 'I've been here before'- style gravitas), and based on what I saw the Fox News questioners, who did a manful job. 

I still say that the upcoming Iowa Straw Poll doesn't matter, but I consider these to be 20 minutes well spent.
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* I am trying to think of a comparable previous case of a national candidate displaying a similar gross error of basic factual understanding. I'm not talking about non-mainstream views, or of controversial goals or interpretations. I mean someone who clearly did not know how the American government works, although being part of it. If someone can top this, I'll be interested to hear it.