As explained here, there's little or no common ground between the parties on the question of how to make Medicare fundamentally sustainable. That's why House Republicans voted to privatize Medicare, while President Obama wants to give Medicare's Independent Payment Advisory Board more power to change the health care system, and neither party wants anything to do with the other's prescription.
But there are any number of ways to cut Medicare spending without "fixing" the Medicare debt problem -- from means testing, to raising the retirement age, to reducing reimbursement rates, and so on. Not all of them constitute benefit cuts, but many of them do.
If a grand bargain on spending includes Medicare benefit cuts that both parties buy into, it will further expose the shambolic nature of the last two years' politics. But more to the point, it will blunt Democrats' ability to run against the House Republican vote to privatize, and, yes slash Medicare. And it will hurt Senate Democrats, many more of whom will be up for re-election in 2012 than will their Republicans colleagues. Their opponents won't have Paul Ryan's budget to answer for -- but they will have the Dems' vote for the deficit grand bargain, and the Medicare cuts therein.
As Greg Sargent points out, and Republican congressional aides are happy to confirm, Republicans are eager to keep attacking Democrats from the left on Medicare, just like they did in 2010. The NRSC is pushing poll numbers from a progressive group showing Democrats remain vulnerable on Medicare cuts. And a number of Republicans are reissuing their attacks on Democrats for supporting Medicare cuts in the health care law, even though those cuts are preserved in the House GOP Budget.
If Democrats sign on broadly to more Medicare cuts in the Biden talks, it'll give the guys who want to privatize Medicare plenty of ammunition.