Palin could have picked up refudiate from someone else or come up with it on her own. The question is why she didn't correct it along the way, before she got called on it and felt the need to defend it. After all, the course of our lives is strewn with abandoned misconceptions about words. I'm always struck by how tenacious these are. A word will go right past me five or 10 times before I suddenly have this duh moment. As in, duh, it has a 'c' in it. Or duh, compendious doesn't mean comprehensive at all.
But Palin apparently never had a duh moment with repudiate, probably because she hasn't encountered it often enough.
People don't use it a lot in ordinary conversation - as in, I used to think Peter Frampton was cool, but I totally repudiate that now. You have to frequent the places the word hangs out in, the kinds of books and periodicals that have semicolons in them. [Note he places the emphasis on the second syllable of fre-QUENT. Thank you, Henry Higgins.]
But not even Palin's most ardent supporters would claim that she's been a great reader. They prize her for her attitude and authenticity, not her erudition.
Of course, there are other people who blanch at the thought of a head of state whose speech flows so far from the stream of literate English prose. Fair enough. But inarticulateness doesn't preclude political competence - think of Dwight Eisenhower. As the linguist Mark Liberman put it in the LanguageLog blog, politics is not a vocabulary contest. And it's a mistake to read too much significance into these slips and solecisms.
Take the way the logotariat reacted to Palin's use of verbage in place of verbiage during the 2008 campaign. It's a very common error, and in its way a logical one. The i in verbiage doesn't make a lot of sense if you think, as most people do, that the word is related to verb and verbal. It actually comes from the same root as warble. But in The New Yorker, James Wood took verbage as Palin's own invention and called it a perfect example of the Republicans' disdain for words. Verbage - so close to garbage, so far from language.
That's a pretty clever way for Nunberg to dull his Berkeley barbs and then stick Palin with another one. Nunberg realized there's some political danger in smugness, even as he betrayed it:
Where do you begin with that? With the remarkable condescension of garbage -- so close to trash? Or with the insolence of imagining that faulty usage betrays stupidity and turpitude? One way or the other, it's a form of smugness that transcends partisan lines. People on the right are just as quick to ridicule Obama and Biden for their mistakes.
Yet the well-spoken aren't necessarily wiser or better than the rest of us. Most of the horrors that the human race has had to endure in modern times were inflicted at the bidding of men who spoke in shapely grammatical sentences. Unfortunately, eloquence doesn't come next to godliness. A devotion to language will have to be its own reward. Could we just celebrate that?