Lindsey Graham was sitting in a sedan early one morning and contentedly discussing the various fellow S.C. conservatives who dislike him — Tea Partiers, Constitutionalists, immigration hardliners — when Van Cato, his Upstate regional director, lifted a hand from the steering wheel and said: “That’s the leader of them right there. There’s his sign. He’s running for Greenville County Council.” “Harry Kibler,” Graham, South Carolina’s senior U.S. senator, murmured as he read the campaign poster. “He’s the one that has that prop of your legs sticking out of a toilet in the back of his truck,” Cato added helpfully. Graham...