On Melissa Harris-Perry on Sunday, panelists discussed the fact that Social Security was on the table in fiscal cliff negotiations -- which has "progressives calling foul," said guest host Joy Reid.

She discussed a proposed plan to divorce Social Security benefits from cost of living increases and tie them instead to the "chained consumer price index," which assumes that people will buy cheaper alternatives when products become expensive.

House Minority leader Nancy Pelosi (D-CA) claims that such a shift would not be a benefit cut and would strengthen the program, but others claim it would inevitably lead to reduced benefits.

Reid goes on, "As we await a [fiscal cliff] deal, one of the most looming questions we face is just what aspects of Social Security are on the table?"

Recently, 102 Democrats sent a letter to House Speaker John Boehner (R-OH) requesting that a shift to chained CPI be removed from consideration.

Richard Kim, executive editor of TheNation.com, said it's "absolutely a cut" of "thousands and thousands of dollars a year for seniors," who often live on Social Security alone.

About a quarter of seniors live solely on Social Security, and it comprises the majority of income for 65 percent of beneficiaries, according to the progressive Center on Budget and Policy Priorities.

"The idea that when chicken gets too expensive you buy tuna, and when tuna gets more expensive you buy, what, cat food, that's the real sort of principle behind chained CPI," Kim said.

Reid noted that many progressive organizations support chained CPI, including the Center for American Progress, which claimed the move would only result in a 0.3 percent benefit reduction in a report.

Kim countered that the reduction ends up accumulating over time but added, "The problem with all this is that Social Security is not the problem here. We don't need to be discussing this to reduce the deficit," going on to cite the Bush tax cuts, the Iraq war, Afghanistan, and stimulus spending as major drivers.

Reid said that while she believes Social Security does not contribute to the deficit and that the program is solvent till 2037, "But at some point you do have to deal with it, right? Why not deal with it now? Can progressives get behind that?"

Paul Reyes, of NBCLatino.com, was frustrated that the president's campaign promise that Social Security would not be on the table seemed to have unraveled, claiming that chained CPI, because of its complexity, almost seemed a way to "slip something else by" unnoticed.

He also railed against the fact that politicians left Washington for the holidays without striking a deal. "I don't think it's right to say, 'Oh okay it's Christmas Eve, we're all going home, I'm going to get on Air Force One and fly to Hawaii.' And the Republicans are going -- I don't think it's right."

"People at McDonald's work on Christmas," he went on. "I just don't think they have this right to vacation."

Executive Director of the Congressional Black Caucus Angela Rye said that there are staffers working, but more importantly, "There aren't real negotiations happening. There is posturing in the media. There are hard statements and firm lines drawn in the sand, but there aren't real negotiations happening."

Watch the video, via MSNBC, below.

Visit NBCNews.com for breaking news, world news, and news about the economy