An increase in the Medicare eligibility age, perhaps more than any other proposal getting bandied about in the fiscal cliff talks, would split President Barack Obama from the heart of his political base.

Rep. Emanuel Cleaver II, D-Mo., the chairman of the Congressional Black Caucus, told CQ Roll Call last week that his caucus has been supportive of the president, but he said raising the Medicare eligibility age from 65 to 67 would present a tough choice between backing the president and protecting African-American seniors from bearing the brunt of the change.

As Cleaver noted, African-Americans have much lower life expectancy than whites, so later eligibility affects them far more.

“We obviously have been extremely supportive of the president and we have been the past four years to be sure,” he said. “We would be in a really, really awkward situation if the president made such a proposal.”

The Missouri Democrat said it would be “a request for us to vote against many of our constituents.”