Barack Obama looked as if he needed a smoke and he needed it bad. So there he was, trying to meet the deep, inexhaustible needs of both Iowa activists and the global press behemoth on his first swing across the state, while giving up cigarettes. He was a tad testy. “I’ve been chewing Nicorette all day long,” he told reporters at a press conference in Ames on Sunday, where he was getting irritated at suggestions that he lacked substance and at the specter of his vanishing privacy. The Illinois senator didn’t have on an implacable mask of amiability, as Hillary...