President Obama smashed fundraising records in 2008, collecting $746 million to win what turned out to be the most expensive presidential contest in history.

But four years later, the president's senior campaign advisers say they expect to be outspent by pro-Republican outside groups, including nonprofit advocacy organizations with secret donors and the sky's-the-limit super PACs.

"We are going to be the first incumbent outspent," a senior Obama campaign official told reporters during a background briefing in Washington today. "I think that's clear."

The looming influence of outside groups means that "any spending advantage we might have had is erased," another campaign adviser said.

Obama campaign officials estimate, based on public pronouncements by the groups, that more than $1.2 billion will be spent to help defeat President Obama.

The figure includes a projected $300 million in ad spending by the Romney campaign and the Republican National Committee, plus roughly $1 billion from groups like Restore Our Future, American Crossroads, Americans for Prosperity, and the U.S. Chamber of Commerce.

The president's campaign is on track to raise roughly what it did four years ago, but the Democratic super PAC - Priorities USA Action - has not added much firepower.

"I'm not sitting here with a billion-dollar check in my pocket," one Obama campaign official acknowledged.

Members of the Obama team offered their state-of-the-race assessments at a briefing in Washington, D.C., with several dozen reporters. The campaign stipulated that the officials could not be identified by name.

The briefing came on the same day that a new Bloomberg News poll showed President Obama leading GOP challenger Mitt Romney by 13 percentage points nationally - a finding that one Obama strategist dismissed.

"Do I think we have a 13-point lead?" the strategist said. "No."

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In light of the lopsided cash advantage for Republicans this year, members of Team Obama said they will focus on forcing the disclosure of donors to the outside advocacy groups running ads against the president through public pressure and legal challenges.

"They're going to try to avoid this for as long as they can. After all, they have a vested interest in being able to spend millions anonymously to influence our elections - many of the corporations and individuals funding their organizations don't want their agendas to receive scrutiny from the press or the public," said Obama campaign manager Jim Messina in a blog post Tuesday.

"We can make sure they don't get away with hiding these donors - or their agendas," he wrote. "But it's going to take a lot of us standing up, putting our foot down, and saying 'Hell no.'"

Even so, the fact that GOP outside groups are spending $20 million during the last 10 days in June represents a "harbinger of things to come," one Obama campaign official warned today.

After Romney raised more money than the Obama campaign for the first time in May, members of the president's re-election effort predicted "another huge month" for the Romney camp in June - more than $100 million, they say. Officials said they don't expect the president to match that number, and they declined to offer specifics on the pace of fundraising so far this month.

The officials said the president was still more engaged with his "day job" than he was with his re-election bid.

"We don't have a daily dialogue with him," one adviser said.