LIEBERMAN IN CONTEXT…. We talked yesterday about new reports on Joe Lieberman’s financial support for Republican congressional candidates before Election Day, on top of his work on behalf of John McCain and Sarah Palin. I argued that if Senate Democrats had known about this before their recent caucus vote, the outcome probably would have been the same.

Ezra had a different, and thought-provoking, look at the same circumstances.

Take the recent line on Joe Lieberman seriously. Imagine he simply was a Republican. A generic moderate Republican. A Chris Shays Republican. And as a Republican, he voted frequently against Democratic priorities, attacked progressive bills on the cable channels, and endorsed his fellow Republicans for office.

But imagine too that his state was changing, and his party looked unlikely to retake power, and for reasons of opportunism, he began talking with Harry Reid about switching to the Democratic Party. And Reid convinced him, though it took a lot of inducements and a lot of forgiveness, because in the Senate, one more vote can be worth a lot. Would most observers understand that as a coup for the Democrats or a capitulation to the opportunist? Or maybe both?

Interesting; I hadn’t thought about it quite this way. If Lieberman was a Republican — an actual, self-identified, caucusing Republican — and wanted to switch parties, there probably would be a much stronger willingness to accept and indulge his campaign efforts on behalf of GOP candidates. This was certainly the case seven years ago when Jim Jeffords crossed the aisle. Party-switchers are necessarily coups for the receiving party, even if that means accommodating the partisan work he/she did before the switch.

Indeed, it would have to be a coup precisely because of what party association entails. If Republican Lieberman were approaching Reid right now about a switch, he’d effectively (if not literally) be telling Reid, “I’m going to start voting with Dems on key issues, endorsing Democratic candidates, and contributing financially to Democratic campaigns.”

Of course, this helps underscore the one aspect of Lieberman’s conduct that offends Democrats most: betrayal. If he was a Republican who’s now prepared to join the Democratic caucus, there’d at least be some consistency to his decision making — he would have spent 2008 doing what other Republicans were doing in support of the GOP ticket and down-ballot candidates. That’s irritating, but it’s not treachery.

Except, Lieberman wasn’t an actual Republican, and the context matters. He led “Democrats for McCain” after promising his own constituents to help elect a Democratic president. Just as importantly, he used his role as a “Democrat” to lend credibility to the Republican message and its candidate slate. Had Lieberman been a genuine Republican, this dynamic wouldn’t have existed.

And taking Ezra’s thought experiment a little further, suppose Lieberman was now poised to leave the Republican Party, and Democrats were prepared to welcome him with open arms, including “a lot of inducements and a lot of forgiveness.” How rational would it be for the Senate caucus to then make Lieberman the chairman of the committee responsible for oversight of a Democratic administration?

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.