Early this morning, readers were treated to Joe Lieberman's latest: an op-ed in support of escalating the war in Iraq.

BarbinMD dissects it beautifully, as usual. I have only one thing to add, which wouldn't normally call for a new story. But because this is Lieberman we're talking about, there can be no doubt about what the meaning of this positioning is.

The most revealing part of the essay appears at the very bottom of the column. And Joe Lieberman didn't even write it:

The writer is an Independent Democratic senator from Connecticut.

Yes, I know that Joe Lieberman says he'll caucus with Democrats. And that's... useful.

And yes, I know that we're a "big tent," and even that Lieberman is often a reliable vote on a wide range of issues that make Democrats Democrats.

But let's discuss what makes Lieberman Lieberman. Joe Lieberman found his niche in the late 90s by piping up occasionally about issues of "values," and separated himself from the pack with his willingness to be strongly critical of President Clinton's peccadilloes. That came in handy, at a time when then-candidate Al Gore needed to distance himself without distancing himself. But once that play had run its course, Lieberman turned it into his raison d'etre. There was a market, it seemed, for a Democrat who would go on record criticizing other Democrats. And that kept Joe Lieberman's phone ringing, post-2000 campaign.

Today, that manifests itself in his stance on the war. He's the Democrat who'll bash Democrats, and provides the "bi" fig leaf in "bipartisanship," when that fig leaf becomes necessary to sell outlandish idiocies like escalating the Iraq war in the face of 89% public opposition.

So it's worth remembering that the reason Joe Lieberman is an "Independent Democrat" is that Connecticut's actual Democrats threw him off their ticket in 2006. Why? Because they'd grown tired of the way Lieberman's hook was manifesting itself. Tired of being the state responsible for the Senate's professional contrarian. Tired of being responsible for the Democrat who allowed George W. Bush to maintain the fiction that his war -- and now its escalation -- is a "bipartisan" affair.

Only Senators who win their primaries get to bestow the imprimatur of "bipartisanship."