Obama is rattled because he got so used to fawning media treatment he thought he could coast the rest of the way. Palin’s speech was thoroughly humiliating to him because there was no way to respond to the basic charge — that he hasn’t done a whole hell of alot beyond being slick-talking careerist. Hillary spent her whole campaign harping on his inexperience but didn’t have the stones or the communication skill to lay into him like Palin. And 38 million people saw it live.
Yup, he’s a front-runner who believed his own hype (cue Public Enemy, “don’t believe the hype”) once a front-runner horse is passed he loses it, I can smell the fear from here.