She pulls at the heartstrings of the Republican base, but in addition to all the peculiar problems of her own design, Sarah Palin has one obstacle she cannot overcome. Republicans like to choose the next in line—and she isn't. Sarah Palin is the bright red thread in the dull, grey fabric of the Republican Party. She is charismatic, quirky, melodramatic, and fervently anti-choice, anti-gay, and anti-Obama. But there's one thing she'll never be—the GOP nominee for President in 2012. Palin has the most intense grassroots base of any potential candidate, in the true-believing core of the party. And that's worth...