Liberal journalists love writing about divisions in the Republican Party--social conservatives vs. moderates, Tea Party vs. establishment, and so forth. That gives stories about Democratic infighting a man-bites-donk quality. One such story is a feud between Markos "Kos" Moulitsas, the Angry Left's answer to the Htoo twins, and Matt Bennett and Jim Kessler of Third Way, a Democratic think tank that describes itself as representing "Americans in the 'vital center.' "

It started with a Moulitsas post in which...