WASHINGTON -- President Barack Obama will enter high-stakes budget negotiations firmly committed to seeing the tax rates for high-income earners rise to pre-George W. Bush levels, he assured a gathering of progressive and labor leaders on Tuesday.

"I am not going to budge," he told the group, according to an attendee who relayed material from the meeting on condition of anonymity. "I said in 2010 that I'm going to do this once, and I meant it."

The White House did not immediately return a request for comment, but two other sources who attended the meeting confirmed the quote. The administration seems to have staked out a firmer position than during the first stand-off over the Bush-era tax cuts, in November and December of 2010, leaving the impression that it won't sign off on a compromise that doesn't increase the tax burden on the wealthy as a means of paying down the deficit.

How the president plans to effect that outcome is still unclear. Top Democrats in the Senate have said they would be comfortable letting all the tax rates expire -- as they are scheduled to do -- at the end of the year, after which they will put together a tax cut bill that would re-establish the Bush-era rates for incomes below $250,000.

Several sources at the meeting said the president was, as one noted, "more nuanced than going off the cliff." Obama hopes to place "maximum pressure on House Republicans so at the end of the day he may be able to budge them," the source added.

"It seemed like he meant it," the first source said. "That suggests that they are ready to go over the ledge."

Following the meeting, a handful of attendees spoke briefly to the press, praising Obama for vowing to firmly oppose an extension of the tax cuts for the wealthy.

"It was a very, very positive meeting," said AFL-CIO President Richard Trumka. "We're very committed to making sure that the middle class and workers don't end up paying the tab for a party that we didn't get to go to, and the president is committed to that as well."

"The president was really standing firm on taxes," said Neera Tanden, president of the Center for American Progress. "Everyone in the room talked about how much they have the president's back in this fight."

The expiring Bush-era tax cuts are just one component of a larger budget deal that needs to be hammered out with congressional Republicans, the details of which remain unclear. White House Press Secretary Jay Carney ducked a question during Tuesday's press briefing as to whether Obama would be willing to put cuts to entitlement benefits on the table in negotiations with Republicans. Instead, Carney pointed to the $340 billion in savings from entitlement reform already in Obama's plan.

The first source said that the president "seemed to agree that Social Security" should not be part of any grand bargain because it "didn't add to the deficit."

Carney also left the door open to the idea of raising the threshold for extending the Bush-era tax cuts to $500,000 or $1 million. Obama drew the line at $250,000 in his proposal.

"He is not wedded to every detail of that plan," Carney said, when asked specifically if Obama would be willing to raise the limit.

In the process of putting together a far-reaching piece of legislation, the president will have the help of the progressive community's political arms. All of the meeting's attendees pledged to keep their election-season campaign apparatuses intact for purposes of drumming up support for the president's budget priorities.

Obama asked the attendees to focus their efforts on pressuring House Republicans to reach an agreement on the tax cuts, reminding them that the American people made clear in last week's elections that they want to see the wealthiest pay more in taxes, according to a source familiar with what was discussed at the meeting.

AFSCME president Lee Saunders, who attended the meeting, said his members are prepared to devote as much energy to pressuring Republicans to reach a balanced debt deal as they put into the campaign season.

"We're going to have our folks engaged, just like they were in the election," Saunders said. "They're going to be engaged in this campaign."

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    <a href="http://www.whitehouse.gov/about/presidents/georgewashington">1st President</a> of the United States (Photo by Three Lions/Getty Images)

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    <a href="http://www.whitehouse.gov/about/presidents/thomasjefferson">3rd President</a> of the United States (Photo by Hulton Archive/Getty Images)

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    <a href="http://www.whitehouse.gov/about/presidents/andrewjackson">7th President </a>of the United States (Photo by Hulton Archive/Getty Images)

  • Abraham Lincoln (1861-65)

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  • Grover Cleveland (1885-89, 1893-97)

    <a href="http://www.whitehouse.gov/about/presidents/grovercleveland22">22nd</a> and <a href="http://www.whitehouse.gov/about/presidents/grovercleveland24">24th President</a> of the United States (Photo by National Archive/Newsmakers)

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    <a href="http://www.whitehouse.gov/about/presidents/williammckinley">25th President</a> of the United States -- McKinley was elected to a second term, but it came to a tragic end when he was assassinated in September 1901. (Courtesy of the National Archives/Newsmakers)

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    <a href="http://www.whitehouse.gov/about/presidents/franklindroosevelt">32nd President</a> of the United States (Photo by Keystone/Getty Images)

  • Harry Truman (1945-53)

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    <a href="http://www.whitehouse.gov/about/presidents/dwightdeisenhower">34th President</a> of the United States (Photo by Keystone/Getty Images)

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  • Richard Nixon (1969-74)

    <a href="http://www.whitehouse.gov/about/presidents/richardnixon">37th President </a>of the United States -- Nixon was elected to a second term, but resigned in August 1974 over the Watergate scandal. (AFP/Getty Images) <em><strong>Correction:</strong> A previous version of this slide incorrectly listed Nixon as the 25th President of the United States.

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    <a href="http://www.whitehouse.gov/about/presidents/ronaldreagan">40th President</a> of the United States (Photo credit should read -/AFP/Getty Images)

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    <a href="http://www.whitehouse.gov/about/presidents/williamjclinton">42nd President</a> of the United States (LUKE FRAZZA/AFP/Getty Images)

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    <a href="http://www.whitehouse.gov/about/presidents/georgewbush">43rd President</a> of the United States (SCOTT OLSON/AFP/Getty Images)

  • Barack Obama (2009-Present)

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