I still don't think it's too late for Sarah Palin to turn it around, at least in large part, if she suddenly decided to play by the rules that normal candidates follow. Policy expertise can be bought and faked; party leaders, whether they're national columnists, interest group leaders, or locals in Iowa and New Hampshire, can be schmoozed. It increasingly appears that either she is constitutionally incapable of doing those things or just has no interest in it, and even if she does them there's no guarantee she would be nominated...but it is clear now, as it has been from the start, that the normal rules of politics apply to her regardless of what she or anyone else thinks.
Nate Silver puts Palin's latest numbers in context:
I don’t think much is accomplished by comparing Ms. Palin to Charlie Sheen, but it seems entirely fair to compare Ms. Palin to someone like Pat Buchanan, a factional candidate who had his impact on the Republican primaries but ultimately had limited upside.
My own view is that her Tucson tone-deafness hurt her - but not that much with her core supporters. Unless she slips firmly into the second tier of candidates, I don't think she is the equivalent of Pat Buchanan. For one thing, Pat Buchanan had never run as veep on a national ticket. And, while Pat has his charms, he does not provide any starbursts. And the question, of course, cannot be considered in a vacuum. She has to be compared with the actual competition.