WASHINGTON -- Top aides to President Barack Obama's presidential campaign have long prepared for a general election battle far more divisive and nasty than the one that took place in 2008.

The rapid growth of super PACs has enabled deep-pocketed donors to spend unlimited sums of money on negative campaign ads. Members of some conservative circles have consistently expressed the belief that the president was not fully "vetted" during the '08 campaign, and that a few ads focusing on his controversial associations could have perhaps moved the dial. Moreover, at the top of the ticket, there will be no John McCain, who famously decided during his presidential campaign that racially provocative attacks were out of bounds.

"I see nothing in Governor Romney's performance so far that suggests that he sees many lines, or that there are lines that he wouldn't be willing to cross or allow," David Axelrod, a chief adviser to the Obama campaign, told The Huffington Post during an interview in his campaign office on Monday. "I thought it was one of the great moments of McCain's campaign when he stood up to that woman [who called Obama a Muslim]. I don’t think he lost points because of it. I think it was a high character moment and people want that in their president."

So Obama's reelection team in Chicago wasn't caught off guard when The New York Times reported Thursday morning that a conservative super PAC, bankrolled by Joe Ricketts, the founder of TD Ameritrade and the owner of the Chicago Cubs, was plotting a $10 million ad campaign focusing on the president's ties to his former pastor, the controversial Reverend Jeremiah Wright.

But the campaign still viewed the story as incredibly consequential. The prospect of these types of character attacks had surfaced earlier than expected, and aides thought the story had the potential to place the campaign in one of the five most important moments of the election.

Campaign manager Jim Messina carefully crafted a statement denouncing the "hate-filled, divisive campaign of character assassination" and accusing Mitt Romney of falling "short of the standard that John McCain set, reacting tepidly in a moment that required moral leadership."

Earlier in the day, Romney had told reporters that he hadn't read the Times story, leaving him incapable of offering a response. But by the time that Messina was attacking the former Massachusetts governor for quivering morals, his campaign had already sought distance from the Wright ad proposal.

"Unlike the Obama campaign, Gov. Romney is running a campaign based on jobs and the economy, and we encourage everyone else to do the same," Matt Rhoades, Romney's campaign manager, said in a statement. "President Obama’s team said they would 'kill Romney,' and, just last week, David Axelrod referred to individuals opposing the president as 'contract killers.' It's clear President Obama’s team is running a campaign of character assassination. We repudiate any efforts on our side to do so."

Even Ricketts himself tried to distance himself from the proposal by midday Thursday, with a spokesman saying it "reflects an approach to politics that Mr. Ricketts rejects."

Though Romney himself brought up Jeremiah Wright during an interview on Sean Hannity's radio show in early February, he seemed hesitant to see the Wright debate revived. By offering a statement from Rhoades, a reticent figure who rarely talks to the press, the Romney campaign was signaling a deep sense of unease with the topic. An hour later, the campaign further signalled its seriousness, when it granted an interview with the candidate to the conservative website Townhall.com.

"I repudiate the effort by that PAC to promote an ad strategy of the nature they've described," Romney said. "I would like to see this campaign focus on the economy, on getting people back to work, on seeing rising incomes and growing prosperity ... And I think what we've seen so far from the Obama campaign is a campaign of character assassination. I hope that isn't the course of this campaign. So in regards to that PAC, I repudiate what they're thinking about."

It seems unlikely that that will serve as a sufficient denouncement of the attempts at character assassination, as the Obama campaign has little incentive to let Romney off that easy. What's more, Romney, in the end, has very little control over what third-party groups end up doing with their money. If Ricketts decides that he still wants to write that $10 million check, there are plenty of conservative ad-makers and media buyers willing to cash it for him.

If that ends up happening, the Obama campaign wouldn't be entirely displeased. The president has long polled best on questions about his personal attributes. People like him. And the prevailing sentiment among top aides is that the Reverend Wright issue has been chewed over by the public before and won't change voter's minds if it comes up again.

"Nobody in the country hasn't seen those tapes from last time around. It is not like that attack hasn't been introduced," said one top aide, before the Times story was published. "It may have been effective then because nobody knew who the president was. But they have been with them for four years. Re-surfacing it now won't work. His leadership and character attributes have always been some of his strongest when you ask voters."

Watch an attack ad John McCain declined to air in 2008:

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