Kerry impressed me. His tone was good—challenging but not belligerent. He was articulate and poised, and he had good control of his material. Bush was weak, though not terrible. He didn’t seem well prepared, though perhaps he was and Kerry took him out of his game. Bush got fired up a few times, but didn’t seem to be able to channel his passion into effective responses. Instead he would fall back onto his talking points, which were solid, but too often not in the context of the question he was addressing. He wasn’t able to say much of substance once he got beyond his talking points.
I suspect that those who have followed the campaigns will seize on the holes in Kerry’s statements—inaccuracies, inconsistencies, distortions—and discount his performance. Those same people will have a tendency to “fill in the gaps” in Bush’s responses and count them as beefier than they were.
Those less familiar with the issues and the candidates’ previous statements, however, lack the benefit of perspective and interpolation. They will have to rely merely on the night’s performance, and I believe this will work to Kerry’s advantage. I expect the race to tighten somewhat.
One last note: my initial reaction to Bush, whether he is debating, speaking, or giving a press conference, is almost always far worse than it is on second viewing. I’m not sure why this is, but I invariably think he did poorly only to like his performance much better on review.
Update: I've just been zipping around seeing what other bloggers had to say, and the question of who won on substance versus who won on style seems to keep coming up. I think it's clear that Kerry won on style, but I believe he won on substance as well. To echo what I said above, those who say Bush won on substance are biased by the truth. They know the facts and use them as a measuring stick to judge each candidate. But someone who doesn't know the facts will perceive Kerry as speaking with more breadth and confidence on the specifics while seeing Bush recite talking points about mixed messages (which weren't in evidence within the frame of this 90 minute debate). Kerry comes off as more substantive in this context.
Another thought: the exchange on Korea was one of the better presidential debate moments in memory. There are clear philosophical differences between the candidates and they were made plain. However, even here I must repeat my point from above: everyone watching will understand that Bush and Kerry disagree on what to do about Korea, but someone without previous knowledge (i.e. most viewers) probably doesn't have a clue about how we got here or which approach is best. So what should be a standout moment in the debate will probably end up being dismissed by most watchers.