Non-Verbal Reactions in Interviews vs. Debates: I wonder if the reason Palin is decent in a debate and so horrible in an interview is that in a debate, she's not receiving obvious non-verbal feedback from the questioner. In a one-on-one interview, the interviewer will be reacting to what she says, and as she spews her gibberish, if the interviewer's eyebrows go up, Palin knows she's been caught out. This in turn makes her conscious that she's going to get a follow-up, so she has to start thinking on that, or trying to fix her answer as she continues to speak.

Perhaps this is a male/female thing -- women are socially trained to be more empathetic (though, of course, any particular woman can be just as boorishly insensitive as any particular man), and women tend to be more sensitive to non-verbal communication. In a debate format, she's on her own, with virtually no non-verbal reaction to her words. While her debate opponent may provide some non-verbal reactions, that's her *opponent*, and can be safely ignored (or has already been anticipated in debate prep). The moderator has a job to minimize any non-verbal reactions, by virtue of needing to be fair to all the participants in the debate. Thus, there is no really significant reaction to her remarks in real time to drive her train of thought off the tracks.

I think that more than anything else is why she did so poorly in the interviews while doing pretty decently in the debate -- her message was not being non-verbally critiqued in real time, and that allowed her to plow through her prepared talking points unhindered by any need to actually think.

Note: Blink tag on Palin's name explained here.