Look, as far as effects, debates mostly don't matter. On top of that, it doubly doesn't matter (at least with respect to the nomination contest) what Gingrich, Cain, Santorum, and Huntsman do...they aren't going anywhere, and everyone knows it or should know it. Same, basically, with Ron Paul. Bachmann? Really, I basically think the same is true with her, although she's certainly going to get plenty of votes Saturday and may well get plenty when the voting begins...but how she does in debates at this point isn't going to change that much. And there's really nothing much going on for Romney in these, either. He has to avoid self-immolation, but that's a low bar. He gets to look far more presidential than the others. He did both of those things.
Tim Pawlenty had something on the line tonight, though; he's desperately trying to convince party actors that he's really viable after all. As I said over at Greg's place today, he probably is to the point of needing to manufacture some good news about his candidacy. I don't think he did that, although if he does somehow manage to do it on Saturday at the Straw Poll then his debate will look great in retrospect, so that's something I suppose. However, the real test of whether Pawlenty manufactured good news for himself will come in the postmortems in the GOP-aligned press, and I'm not energetic enough tonight to follow any of it.
Also, I thought the questioning was mostly overrated, judging from the early positive reviews I saw. But that's okay; we'll have plenty more debates before this is all over.