Krugman nails it:

The Resentment Strategy :

But don’t be fooled either by Mr. McCain’s long-ago reputation as a maverick or by Ms. Palin’s appealing persona: the Republican Party, now more than ever, is firmly in the hands of the angry right, which has always been much bigger, much more influential and much angrier than its counterpart on the other side.
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What the G.O.P. is selling, in other words, is the pure politics of resentment; you’re supposed to vote Republican to stick it to an elite that thinks it’s better than you. Or to put it another way, the G.O.P. is still the party of Nixon.
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Can Mr. McCain and Ms. Palin really ride Nixonian resentment into an upset election victory in what should be an overwhelmingly Democratic year? The answer is a definite maybe.
By selecting Barack Obama as their nominee, the Democrats may have given Republicans an opening: the very qualities that inspire many fervent Obama supporters — the candidate’s high-flown eloquence, his coolness factor — have also laid him open to a Nixonian backlash. Unlike many observers, I wasn’t surprised at the effectiveness of the McCain “celebrity” ad. It didn’t make much sense intellectually, but it skillfully exploited the resentment some voters feel toward Mr. Obama’s star quality.
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But the Democrats can’t afford to be complacent. Resentment, no matter how contrived, is a powerful force, and it’s one that Republicans are very, very good at exploiting.