Democrats.

The talk of any deal with congressional Republicans — and for now, it’s just that: talk — has liberals worried the White House will give in to changes to safety net programs including Medicare, Medicaid and Social Security.

Republicans say such changes are an essential part of any big deal. And Obama previously has been open to a number of reforms that irk the liberals, such as raising the retirement age of Medicare, means-testing and adopting an inflation calculation, known as chained CPI, for Social Security.

Inevitably, if there is an agreement on a big deal, Democrats will have to get on board for it to pass. But the 2012 election brought in new Democratic members of the House and Senate who are more liberal and more outspoken, strengthening the left wing of the caucus.

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One hundred and seven of the 200 House Democrats signed a letter to Obama threatening to vote “against any and every cut to Medicare, Medicaid or Social Security benefits — including raising the retirement age or cutting the cost of living adjustments that our constituents earned and need.”

Instead, they want the White House to “rely on economic growth and more fair revenue-raising policies to solve our fiscal problems,” like getting rid of subsidies for big businesses and raising taxes on the wealthiest Americans.

“I only know one thing: I’m against cutting Social Security, Medicare, Medicaid,” said Rep. Keith Ellison (D-Minn.), co-chairman of the Congressional Progressive Caucus in the House. “I don’t really care who is pushing it. It doesn’t matter who says it’s a good idea. It’s a bad idea.”

Ellison said the early resistance from House Democrats to cutting benefits was an indication “they won’t be able to do it.”

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A second letter, spearheaded by Reps. Alan Grayson (D-Fla.) and Mark Takano (D-Calif.) and supported by the Progressive Change Campaign Committee, simply states they pledge to vote against any proposal they see as a benefit cut.

The letter has been signed by 25 other members of the Democratic Caucus.

“I had a reporter ask me recently, ‘Is this just like the Grover Norquist No Tax Increase Pledge,’ and I said, ‘Yeah, sure, just like a fish is like a bicycle,’” Grayson said on a conference call with PCCC supporters. “If you promise that you won’t raise taxes on millionaires and billionaires and multinational corporations, that shows who you think you really represent. And if you say you won’t cut benefits for old people, sick people, poor people, that shows who you care about, too.”

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They also have an important ally in House Minority Leader Nancy Pelosi (D-Calif.), who said at a recent press conference that she’s all for making entitlement programs “more fiscally sound,” but including things like raising the retirement age or chained CPI would simply be taking “a scalp” or a “trophy” for the GOP.

Rep. Peter DeFazio (D-Ore.) said he was sympathetic to what the president was trying to achieve, but he, too, was a firm no on changes, especially to Social Security.

“He wants to get a grand bargain, and the Republicans are totally insistent that he can’t have a grand bargain unless something is done about entitlements,” DeFazio said. “I don’t think it’s the place he wants to go first or second, but he’s trying to get them to the table.”

And DeFazio rejected the idea that Democrats are resistant to making changes to entitlement programs, albeit his ideas were unlikely to get very far.

“Have Medicare negotiate prescription drug prices for every person on Medicare. Sell an at-cost premium through Medicare, get rid of the private insurance companies and you’d save $25 billion a year,” he said.

Obama’s supporters in outside groups are fretting, as well, that if he’s desperate to make a deal with Republicans, he’ll agree to cuts.

“For the president to actually agree to damage the Democratic Party brand by agreeing to cuts to the Social Security system and Medicare and Medicaid, that would really be astonishing,” National Organization for Women President Terry O’Neill said on the same PCCC call as Grayson.

Just last week, Obama’s economic adviser, Gene Sperling, said on NBC’s “Meet the Press” that the president remained open to means-testing and chained CPI in exchange for more revenue through tax reform.

“These are tough things the president agreed to,” Sperling said.

Republicans, meanwhile, have said that the president got his revenue in the fiscal cliff deal, and more revenue, even through tax reform, is a nonstarter unless entitlement reform and spending cuts are on the table.

“Listen, we’ve got a structural spending problem that has to be addressed,” Speaker John Boehner (R-Ohio) said on CNBC last week. “The president’s sequester is in effect, and it will be in effect until there’s an agreement on cuts and reforms that put us on a path to balance the budget over the next 10 years.”

Over in the Senate, Bernie Sanders (I-Vt.) said flatly that the president was “dead wrong” to consider chained CPI.

“The veterans community does not agree with the president; the senior community does not agree with the president; women’s communities don’t agree with the president. He’s way out of touch on this issue, and I hope he rethinks this,” Sanders said.

While Sanders has been a longtime opponent to cuts to government programs, newer members are joining him in his opposition.

“Chained CPI is just a fancy way to say, ‘Cut benefits for seniors, the permanently disabled and orphans,’” Sen. Elizabeth Warren told Salon. “Our Social Security system is critical to protecting middle-class families, and we cannot allow it to be dismantled inch by inch.”