a light switch coming on." No matter what moves Mr. Romney made, the president said, he and his team were going to cut him off and block him at every turn. "We're the Miami Heat, and he's Jeremy Lin," Mr. Obama said, according to the aide. Since then, Mr. Obama has been working at a furious pace, headlining three times as many fund-raisers as George W. Bush did during his 2004 re-election campaign, according to Mr. Knoller. When local campaign staff members ask him what they need to do better, he talks about himself instead. "I need to be working harder," he recently told one state-level aide. He recently began preparing for the presidential debates , reading up on Mr. Romney and his positions. One danger is that he could sound grudging or smug by indulging in his habit of scoring others (as in, "You're likable enough, Hillary," one of his worst debate moments from 2008). As he slashes into Mr. Romney's arguments, he sometimes cannot help letting crowds know what he thinks of his rival's political skills. "When a woman right here in Iowa shared the story of her financial struggles, he gave her an answer out of an economics textbook," he said about Mr. Romney in May, his tone incredulous. Though Mr. Obama quizzes his team on all aspects of the campaign, he is concentrating most on the rhetorical challenge of making a case for a second term. He has worked on making his stump speech tighter, less