He did not, to my recollection, participate too fervently in the endless ratcheting of the more, better Democrats movement, preferring to cultivate an image as a wonkish, though admittedly partisan, observer and commentator, but Matt Yglesias made the headline, so Matt Yglesias gets the infamy:
You may recall how the Donk protested its innocence back in the bygone days of Total Republican Dominance. Don't blame us!, the Donkle cried. Not even the traitorous quisling Jeffords in those heady, pre-9/11 times helped much with his defection to the Donk bosom. Then slowly, slowly, like the first mutant fish hauling its bony, wheezing body out of the slime and onto the sand, the Donk slipped back into power. But when it won Congress, it wasn't enough, and when it won even more Congress and the Presidency, it wasn't enough, and when at last it achieves sentience and launches Judgment Day on its unsuspecting, soft, human creators . . . still, it will not be enough.
In this regard, Democratic voters are really no different than the Rapture-ready Republican rubes they are ever-willing to mock as credulous fools, worshiping likewise at a church whose eschaton is ever-imminent but never-arriving.