"As a corporate raider, he shipped jobs to China and Mexico. As governor, he did the same thing," said one Obama commercial.
Next came criticism of Romney's finances.
"Tax havens, offshore accounts, carried interest. Romney's used every trick in the book," another Obama ad says, chiding Romney for refusing to release more of his income tax returns. His reluctance to do so "makes you wonder if some years he paid any taxes at all," the ad says, offering no evidence to support that claim.
Sara Fagen, a Republican strategist who was White House political director under George W. Bush, predicted that Obama's shift in tone from four years ago could depress turnout among young people and other constituencies he'll need in a close race.
"His only path to victory is slash and burn, but it flies in the face of his messaging in 2008," Fagen said. "Voters think he's a good guy, he's a good family man. But when the campaign is as negative as it is, it gives them reason to believe he's just another politician."
Bush's successful 2004 re-election campaign made a similar calculation against Democrat John Kerry, running a heavy level of negative ads against the Massachusetts senator immediately after he locked up his party's nomination that spring. The Bush campaign got a key assist from Swift Boat Veterans for Truth, an independent group that ran ads questioning Kerry's military record.
Bush, like Obama, had been elected on a promise to bring partisan factions together but saw his job approval rating sag during the unpopular war in Iraq. His re-election calculation proved successful. He defeated Kerry by a 51-48 margin, carrying most major swing states.
Bob Shrum, a Democratic strategist who oversaw Kerry's campaign, said Obama could not rest on a good guy image. Shrum said the strategy the campaign is following is effective.
"If people thought the ads were out of bounds or about something that wasn't fair or relevant, it would be a different story. But they don't think that at all," Shrum said, adding: "'Obama the positive uniter' is not in the cards at this point."
Associated Press Deputy Polling Director Jennifer Agiesta contributed to this report.
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