James Joyner and Steven Taylor ponder the cognitive dissonance (or perceptual screens) that allow partisans to think their party never resorts to “dirty tricks” while the other does so routinely. Helpfully, Steven Bainbridge produces an incomplete catalog of Democratic offenses, perhaps as evidence of both sides of this phenomenon.

Bainbridge’s post is in reaction to a post by Kevin Drum that argues liberals “still aren’t as dedicated to [their] cause as conservatives are to theirs.” Pondering this point over breakfast (about 50 feet east of where I’m sitting in the Palmer House), I concluded liberals (or, rather, Democrats) aren’t as committed as Republicans because the Democrats are more fractured into multiple interests who often have diametrically-opposed values on important dimensions—consider, for example, the strong religious faith of most African Americans versus the highly secularized, mostly-white “professional” left, or the divergent interests of organized labor (who favor a cartelized labor market) and the working (and non-working) poor. Obviously this isn’t an especially keen insight, but it may go some ways toward another explanation of why the DNC failed to rally support for Kerry/Edwards in the way the RNC did for Bush/Cheney.

More here.