Despite a torrent of criticism from the media, Democrats and even some in her own party, Sarah Palin remains the hottest brand name in politics. Her recent resignation was perplexing. It’s raised doubts about her viability as a potential presidential candidate. Still, she remains extremely popular with the GOP grass roots, and most Republican Party leaders would jump at the chance to have her headline one of their events. That’s the picture that emerges from interviews with dozens of GOP state and local leaders from across the country. As part of an effort to gauge Palin’s popularity with the rank...