I agree with Polnut's analysis; all the talk about 'zingers' was misdirection, and it seems to have thrown Obama off his game.
I don't understand all of the complaining about Lehrer. He let the candidates talk. As far as I'm concerned, that's a good thing - as a debate viewer, I'm always frustrated by moderators who insist on strict adherence to the arbitrary time limits that have been set beforehand.
He actually provided the best debate moderation I've seen; I was very surprised. That Obama was too spineless to seize the opportunity the way Romney did can only speak for him and his campaign.
Lehrer was terrible. His questions weren't even close to focused and he got run over by the candidates while trying to enforce time limits. It was a very weak moderating performance.
I prefer a conversation directed by the candidates - things tend to be more policy-focused that way, which was clearly the case in tonight's debate. A debate fueled by horse race garbage and cheap confrontations may be more interesting, but it doesn't contribute to a healthier political environment. (In other words, I completely agree with Napoleon and TrueFederalist's responses, which appeared as I wrote this.)