As an old-fashioned utilitarian, I would be expected to look fondly onMike Tomasky's essay on the common good as the core of the Democratic message. And I do! Tomasky has expressed a big part of reason that I'm a Democrat, and, I think, the reason that a lot of other people are Democrats too. Democrats are sympathetic and benevolent people who want to help others -- whether the others are poor Americans with no health care or gay couples who want to get married. The same sympathy and benevolent concern for others that characterizes liberalism is at the center of our concern for the common good. (Though an annoying issue arises in the freedom to marry case... see below...)
Digby asks how Tomasky is going to square a bunch of different liberal positions with the common good, and I think good answers are available for some of them. For example, we're against the war because killing our soldiers, squandering hundreds of billions of dollars, alienating our allies, tying down our army, and strengthening the hand of international terrorists is destructive of the common good. Abortion is trickier, because you have to correct the biological and philosophical confusions that make people think the fetus has a mind or is capable of being harmed, and that its welfare figures into the common good. But once you correct these confusions, there's really no good response to the argument that we're all better off if women get more control over when they bring children into the world.