THE ALLEGED REDUNDANCY…. I promise not to spend another day posting incessantly about Joe Lieberman, but there’s one part of yesterday’s discussion that warrants some follow-up.

Lieberman reportedly decided on Sunday that he’d kill health care reform if it included a Medicare buy-in for Americans aged 55 to 64. The position appeared incomprehensible yesterday when evidence emerged showing Lieberman not only embracing this exact same idea as part of a national platform nine years ago, but also publicly endorsing the proposal three months ago.

So, why would the Connecticut senator threaten to kill reform over a measure he claimed to support? In the interest of fairness, it’s worth noting that Lieberman has an explanation, such that it is.

“We’ve got this very strong network and system of subsidies for people, including people who are 55-65 so the idea of the Medicare buy in no longer was necessary because they’re taken care of very well under the Finance Committee proposal,” Lieberman said.

For years, Lieberman had supported the idea of a Medicare buy-in as a promising vehicle for reform, including, as TPMDC first noted this morning, as recently as three months ago. Asked specifically about his position this past September, Lieberman now says that the Senate Finance Committee bill, finalized in October, dealt with the problem of the uninsured so well that the buy-in became redundant.

That’s an interesting spin. Let’s count all of the ways in which it’s unpersuasive.

First, Lieberman says the Finance Committee bill does such a good job for the 55-to-64 crowd, there’s nothing to worry about. That’s vaguely possible, but let’s not forget, Lieberman opposed the Finance Committee bill.

Second, the substance of Lieberman’s claim doesn’t stand up well to scrutiny: “Back when Lieberman endorsed Medicare buy-in in September, the basic subsidies for people in the 55-65 age range were part of the House health care bill, and were clearly going to be part of whatever emerged from the Senate. Nobody imagined a health care bill that would do nothing for people aged 55-65. What’s more, even if Lieberman were completely unaware of even the most rough outlines that health care reform was taking, it’s hard to imagine how he or anybody could believe that Medicare buy-in was desirable on its own but, in combination with other subsidies, so undesirable as to be a cause for filibustering reform. There’s no way anybody would design their policy priorities this way.”

And third, a redundancy is worth killing health care reform over? It’s the kind of thing a senator might say if he’s not negotiating in good faith.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.