Like her or not, Sarah Palin will play a decisive role in who gets the Republican nomination in 2012. Since being plucked out of relative obscurity by 2008 GOP nominee John McCain, Palin has emerged as a celebrity in her own right. Anyone longing for the nomination will have to deal with her persona, her influence, and her supporters. Along with Palin’s notoriety, the rise of the Tea Party movement has created a number of inviting venues for the Palin message. She is now a regular commentator on Fox News, adroitly uses social media to comment on current issues, and...