Shakes here…
Like Neil, I’m rather dubious about the Common Good argument, although for a slightly different reason. In fact, for one big reason—religion. As I noted in the comments to his post, I struggle to see a way to effectively use the Common Good argument to address a possible majority that believes it's in their best interest to require prayer in school, or the teaching of intelligent design, etc. And, perhaps even more importantly than that, I’m concerned that some of the important issues Neil mentions—abortion, gay equality—are so inextricably linked to religion on one side of the debate that the Common Good argument, if it cannot dexterously manage majority viewpoints rooted in religion, will inevitably fail to adequately serve as the core of the Democratic message.