President Obama is attempting to compromise with Republicans by introducing a budget that includes significant cuts to Medicare and Social Security. So far, the plan has succeeded in angering liberals.

Several major advocacy groups have come out against the proposal and pledged to do their best to defeat it.

Becky Bond, the political director for the progressive group CREDO, called the proposal "mystifying."

"The American people are overwhelmingly opposed to cutting Social Security benefits, and if Democrats don't want to go down in history as the party that destroyed one of the greatest social programs of all time, they need to stand up and unambiguously reject the president's proposed cuts," she said.

Jim Dean, chairman of the Howard Dean-founded Democracy for America, similarly called the news "a profoundly disturbing shot across the bow for the progressives who called their neighbors, spent weekends knocking doors and donated millions to reelect" the president. He added a message to Obama: "We are prepared to fight you every step of the way."

Anna Galland, executive director of the online advocacy group MoveOn, called proposed cuts to Social Security "unconscionable."

"MoveOn's 8 million members will not stand by and watch a Democratic President chip away at one of the most successful government programs of all time," she said.

Since February, Reps. Alan Grayson (D-Fla.) and Mike Takano (D-Calif.) have been circulating a letter pledging to "vote against any and every cut to Medicare, Medicaid, or Social Security benefits." About 30 House Democrats have signed it, along with a little over 200,000 members of the public.

Obama's budget, which will be released Wednesday, asks for tax increases in exchange for entitlement reform. But those increases are smaller than in his past proposals. Obama aims to raise $580 billion in tax revenue by limiting deductions for the wealthy, closing loopholes for certain industries, increasing tobacco taxes and limiting retirement accounts for the wealthy.

House Speaker John Boehner (R-Ohio) also criticized the budget, saying it holds "modest entitlement savings ... hostage for more tax hikes."

Senate Democrats have released a budget that includes far more modest cuts to Medicare and Medicaid.

“I don’t want to break the bad news to you, but the president is not the only elected official in the United States,” said Sen. Bernard Sanders (I-Vt.), at the time. “Some of us believe very strongly that it would be absolutely wrong to cut Social Security benefits.”