In addition to what Dylan says, since my name has come up twice in passages quoted by Jon Chait I should say that my argument about abortion and "common ground" isn't exactly the one that Kay seems to attribute to me. To clarify, I'm not saying that concessions will further conflict over abortion by "showing weakness." Rather -- and I take this to be Kay's key point as well -- I don't think that it's remotely plausible to think that concessions will end conflicts about abortion. Incremental regulations of abortion are part of a very conscious, longer-term strategy to re-criminalize abortion in as many jurisdictions as possible. Such compromise legislation may not encourage anti-choice mobilization per se, but nor is there the slightest reason to believe they will make the conflict over abortion go away.
This isn't merely hypothetical: the Supreme Court has explicitly permitted a broad array of abortion regulations since 1992, many states and the federal government have enacted at least some of them, and yet the pro-life movement remains powerful enough to have a veto over Republican presidential candidates. It is naive to believe that the pro-life movement would vanish if it were given even more ground. But this has nothing to do with concessions showing weakness; rather, it's a function of the fact that there's a significant pro-life minority in this country, and as long as abortion is legal, there is no magic formula that could make them go away.
--Scott Lemieux