Washington (CNN) -- Some Democrats have had it -- at least when it comes to reports of what's in a $3 trillion deal being shepherded by President Obama and House Speaker John Boehner.
At issue: large spending cuts on the table that include entitlement programs such as Medicare and Social Security, among other things.
"I don't want to be critical of the president right now," Sen. Dianne Feinstein, D-California, said at a briefing Friday. "We want to be able to make the cuts in a responsible manner so that they're handle-able. And that is a fine art. That's not a blunt sword, that's a scalpel."
On Thursday night, White House Budget Director Jack Lew took "body blow after body blow" from Democratic senators he was briefing on the negotiations, according to a Democratic aide.
The aide said "the caucus exploded" after news broke of a possible deal between Obama and Boehner just before Lew's briefing. Democrats' immediate reaction to the news was that it "would be terrible for their constituents" because it went after all of their "sacred cows."
The aide described Sen. Barbara Mikulski of Maryland as "feisty" in the meeting and said the senator later used the terms "volcanic" and "Mount Vesuvius" to describe the caucus' reaction to the proposal.
Feinstein, in the Friday briefing, said she was frustrated by not getting a "straight answer" from Lew.
"Are discussions going on or not?" she said. "We couldn't get an answer. Then you pick up the morning paper and all you see right-hand (side), above the fold, front page (is) about all these discussions going on. It's hard. It's hard."
The talks, meanwhile, have become a race against the clock. If Congress fails to raise the $14.3 trillion debt limit by August 2, Americans could face rising interest rates, a declining dollar and increasingly jittery financial markets, among other problems.
Republicans are deeply opposed to any deal that raises taxes and insist that only spending cuts are considered.
Obama is pushing for a compromise that allows for deep spending cuts coupled with a raise in revenue by reforming the tax system, a proposal supported by many Democrats.
But it's his willingness to take on entitlement programs that conjures up memories among some Democrats of the tax deal he negotiated with Republicans with the clock winding down at the end of 2010 that reportedly had House Democrats chanting "Just say no!" in a closed-door meeting before eventually voting for the package.
A CNN/ORC International Poll out Friday found that Obama's approval rating has dropped to 45%, driven in part by a growing dissatisfaction on the left with the president's track record in office -- especially the 2011 budget deal he forged with Republicans, which called for a two-year extension of the Bush-era tax cuts.
"Obama's approval rating among liberals has dropped to the lowest point in his presidency, and roughly one in four Americans who disapprove of him say they feel that way because he has not been liberal enough, a new high for that measure," CNN Polling Director Keating Holland said.
CNN contributor and Democratic strategist Donna Brazile said in a recent Twitter message, "What's so grand about cutting the social safety net, eliminating children's health programs, firing teachers and firefighters? That's cowardly."
Some congressional Democrats appeared to be on the verge of open revolt against their own president after hearing some of the details in the $3 trillion plan.
That anger spilled over in a press conference held by several minority congressional caucus groups on Wednesday.
"The debt ceiling issue must be resolved without devastating cuts to Social Security, Medicare and Medicaid, which help millions of American families every day, including millions of Latino seniors and children," said Congressional Hispanic Caucus Chairman Charles Gonzalez. "It's time to find a balanced plan to grow the economy, create jobs, lower the deficit, protect Social Security and Medicare benefits and avoid an unprecedented default crisis."
Congressional Black Caucus Chairman Emanuel Cleaver said African-Americans, seniors and children rely heavily on entitlement programs. "Deep cuts to these critical programs would put the well-being of our families and loved ones at risk," he said. "It is time to cut the political games, instead of critical programs that protect hard-working American families, and get Americans back to work."
Congressional Asian Pacific Caucus Chairman Judy Chu added that as the United States must keep promises to pay our bills, "so too must we keep our promises to our seniors."
"When the average American senior is squeaking by on only $19,000, we shouldn't be subsidizing millionaires' yachts with $140,000 in tax breaks every year," she said. "These three programs are critical to our communities and there is no reason that our seniors or the neediest among us need to struggle to pay their hospital bills."
At a town hall meeting in College Park, Maryland, on Friday, Obama said the idea of a shared sacrifice on a debt deal isn't just his position.
"This isn't some wild-eyed socialist position," he said to laughter. "This is a position that's being taken by people of both parties and no party. ... It's a position that's been taken by every Democratic and Republican president who've signed major deficit deals in the past, from Ronald Reagan to Bill Clinton."
Liberals worry that Obama is "once again surrendering before he has even begun to fight. And in the process, they think, he may be undermining their chances of holding the Senate and regaining the House in 2012," said David Gergen, CNN Senior Political Analyst and a former top aide to several presidents, in a CNN.com commentary.
"It's easy to understand why they are so unhappy. They believe that the GOP handed them a great cudgel for next year's elections when House Republicans voted in favor of the Paul Ryan deficit plan, including its bold but controversial plan to transform Medicare," he added.
Observers believe the special election in New York's 26th congressional district, which had been a Republican stronghold, swung to Democrat Kathy Hochul on the Medicare issue.
"Democrats are itching to run as protectors of Medicare and Social Security; they just love to argue that the mean ol' Republicans want to balance the budget on the backs of the elderly and the poor while preserving tax breaks for fat cats," Gergen said. "That theme has played well for them, so far. Now, from their point of view, along comes Obama proposing Medicare cuts and even putting Social Security cuts in play as part of a mega-deal."
Obama has said entitlement programs need to change in order to be sustained over time. Political analysts also argue that Obama needs to appeal to independents as the 2012 election campaign approaches. But having a fired up base is crucial.
Many groups are threatening to withdraw their support for the president in the upcoming election.
The liberal advocacy group Progressive Change Campaign Committee delivered 200,000 pledges to Obama's campaign headquarters in Chicago last week, demanding he hold their line in debt ceiling negotiations or lose their support.
The group wants a potential agreement to include tax increases on higher income earners instead of cuts to entitlement programs, committee co-founder Adam Green said.
Members of the group said they will not contribute to or volunteer for the president's re-election campaign unless their conditions are met.
"Democrats need to support the will of the American people," Green said in a conference call with reporters. "Social Security, Medicare and Medicaid must be off the table."
"Our position is the middle class has sacrificed enough," Green added.
Obama campaign spokesman Ben LaBolt said the president wants to "strengthen Medicare and Medicaid in the long run and supports finding a bipartisan solution to strengthen Social Security for future generations."
Other groups, including MoveOn.org, AFL-CIO, CREDO Action, Democracy for America, Campaign for America's Future and Change Nation have organized an emergency call-in day to pressure congressional Democrats to stick to the party's principles.
MoveOn members are also calling Obama's re-election campaign in Chicago, the Democratic Senatorial Campaign Committee and the Democratic Congressional Campaign Committee with a message that "if Democrats agree to a deal that hurts working families but does nothing to make the rich and corporations pay their share, it would be a betrayal of core Democratic values and could have serious consequences for the base's involvement in next year's elections," according to Justin Ruben, executive director of MoveOn.org.
MoveOn members are also delivering letters to Democratic congressional leaders -- House Minority Leader Nancy Pelosi, House Minority Whip Steny Hoyer, Senate Majority Whip Dick Durbin and Senate Majority Leader Harry Reid -- calling on them to resist Republican pressure.
CNN's Ted Barrett, Gabriella Schwarz and Alan Silverleib contributed to this report.