I was thinking that Obama's win in South Carolina is a little like Mitt's win in Nevadda. Both won majorities in these respective states, in fact Mitt and Obama both won about the same percentage (Mitt's win seemed bigger because the remaining votewas split between more candidates). In addition, both had wins that were to some extent affected by identity politics, with Obama winning 78% of the black vote (~50% of voters in SC, I think) and Mitt 94% of the Mormon vote (25% of voters in NV).
The big obvious difference is that Mitt's win was only increased by the identity issue while Obama's was driven entirely by it, with Obama coming in third among white voters while Mitt still would have beaten the second place contender (my man Ron Paul) 2-to-1 amongst non-Mormon voters.
We will see how it goes.
That is all.