when you're debating a law professor who's much, much better than you are at packing a lot of information into a 90-second answer:
"All of the details need to be known."
Obama clearly had his Ayers and ACORN monologues memorized, but McCain set them up with a helluva softball straight line. "We need to hear the full extent." "All of the details need to be known."
However many minutes later, Obama looked like the opposite of someone engaged in a cover-up. Rattling off the resumes of the Annenberg Board was a nice touch.
More generally, as Matt Yglesias notes here,
McCain had some okay jabs at Obama that I think impressed some of the CNN panelists and, especially, got the conservative ones jazzed up. But he used a lot of right-wing echo-chamber jargon, never explaining what he meant about trial lawyers and scare-quote “health” and so forth.
As a result, we sometimes had the very weird dynamic of McCain sputtering out an attack that the average voter didn't understand at all, because it was all phrased in conservative-political-insider shorthand, and then Obama giving one of his dense information-packed answers in which he first had to explain to the audience what the hell McCain was talking about before rebutting it. The CNN pundits, in their down-on-Obama period before the poll results came in and told them to be up-on-Obama, kept using "professorial" as an insult. (Compare also: McCain's use during the debate of "eloquent" as an insult.) Now, I recognize all the ways in which "professorial" isn't the ideal mode for political discourse. You wouldn't want a lecture as an inaugural address. But Obama's ability to pack every sixty- or ninety-second unit full of information and explanation, compared with McCain's almost Palin-like or Bush-like repetition of the two or three keywords he had for any answer ("spread the wealth!") was professorial, and, I thought, devastatingly effective.