The problem with the idea of "civility," as we talk about it in public discourse, is that it so easily becomes a blunt weapon.
I want more civility, and better arguments, and more charitable disagreements (which I think will also mean more insightful disagreements, which is really what I'm interested in, what I want more than any particular tenor or tone). But "civility" as we talk about it seems to be exclusively about critiquing other people's rhetoric.
The critique is never a self-critique.
"Civility" becomes another way of delegitimizing others' rhetoric while excusing our own.
I'm not suggesting no one should ever be held accountable, but our mode of doing that seems to guarantee the perpetuation, rather than the end of the unhelpful, uncivil rhetoric. The fact that "civility" is so obviously a self-serving move allows those it's used against to feel wronged, and they double down on their rhetoric. They have a point, when they do that, even though the outrage at being unfairly blamed is childish, and only further defense against any semblance of responsibility.
There have been a couple of moments of self-reflection in the wake of the shooting of Arizona Congresswoman Gabrielle Giffords. Not a lot, but they're good when they happen. One Tea Party head, for example, told Slate, "When we talk about Barack Obama, we've got to be clear ... When we say he's destroying this country we are not saying he's doing it out malicious intent and a desire to cripple us. He has good intentions and he's wrong. I worry when that gets lost." That's a kind of basic level of charity that seems lost, in most of our conversation, and gets more lost, I think, when we have these conversations about the conversations (and meta, meta, etc).
Obama said, in his speech yesterday, that we should "use this occasion to expand our moral imaginations." He said, "Let’s make sure it’s not on the usual plane of politics and point scoring and pettiness that drifts away in the next news cycle.”00
This should be the goal, especially when, after a tragedy, we want to "get serious." Talk of "civility" that isn't self-reflexive doesn't do that, though. It only makes it worse.
I can only think of one example from my lifetime, though, where any effort at improving the quality of discourse, the depth of debate and inquiry, was actually even close to successful in a community-wide way. Godwin's Law, and the added deterrent against Reductio ad Hitlerum, improved the quality of conversations. It only worked, though, because people did use it against themselves, self-reflexively, and stopped some of their stupider arguments. I mean, I know I have.
I can't think of anything else that has done this, though. Any effort that wasn't, ultimately, just a cave man's cudgel.