Nicholas Beaudrot (along with several emailers) wants to know why I'm calling out the Democrats for being rigid and unyielding on abortion when the Republicans have just as rigid a posture on the issue, if not more so. Certainly he's right about the two parties' respective platform language; on the other hand, I think that some of what Beaudrot describes as the Democrats' bigger tent on abortion (the presence of notional pro-lifers in the House and Senate leadership, for instance) is just a function of the fact that the political action on abortion tends to happen on ground that's extremely favorable to pro-lifers, because that's the only ground where the Supreme Court allows legislation of any sort. So yes, there are more Democrats who vote for partial-birth abortion bans, for the born-alive laws, and for limits on government funding of abortion than there are Republicans who vote against the pro-life cause on these issues. But saying that the Democrats are a big-tent party on abortion because they tolerate members who vote against partial-birth abortion is like saying that the Republicans are a big-tent party on the environment because they tolerate members who would vote against, say, dumping radioactive waste in drinking water: It implicitly accepts a very pro-choice reading of what counts as the middle on abortion, and what counts as the extremes.
Such a reading of the abortion issue is, of course, the law of the land, thanks to Roe and Casey, which is why the real action on abortion happens in court appointments and the Presidential elections that produce them. And on that terrain, I do think that there's slightly more space for pro-choice politics in the GOP than there is space for pro-life politics in the Democratic Party. The most important abortion votes that the "pro-life" Harry Reid has cast have been his votes against John Roberts, Sam Alito, Robert Bork and Clarence Thomas; no pro-choice Republican Senator took a similar stand against Bill Clinton's high court nominees, needless to say. Meanwhile, it's true that the Republican Presidential primary is inhospitable to pro-choice candidates, but the reverse is true in spades: It's awfully hard to imagine a reliably pro-life Democrat getting the kind of traction that Rudy Giuliani temporarily enjoyed, and even poor daft Dennis Kucinich felt the need to flip-flop on abortion when he ran for President in 2004. Likewise, it's hard to imagine Barack Obama toying with the idea of a staunchly pro-life running mate, the way John McCain seems bent on toying with the idea of Tom Ridge (or even Joe Lieberman) as his veep. And serious GOP presidential contenders generally keep the pro-life lobby at arm's length to a much greater extent that Dems do with NARAL and Planned Parenthood.
There are good political reasons for this disparity: When the abortion debate turns from specific restrictions to the question of whether to uphold or overturn Roe, the ground shifts in the Democrats' favor. But it's a disparity nonetheless: When the stakes are highest and the potential consequences for abortion law are sweeping, as opposed to marginal, the GOP tends to have a weaker litmus test (though a stronger one than the party used to have) on the issue than the Democrats.
Of course how you approach this question depends in large part on your personal biases about abortion. If you're like me, and think that any middle-ground, "compromise" position on abortion would have to entail returning control over abortion policy to the legislative branch, and implementing, at the very least, more European-style restrictions on second and third-trimester abortions, then the GOP looks like a bigger-tent party than the Democrats. But if you're a pro-choicer who believes that the Roe-Casey settlement is already a middle-ground take on abortion - a sensible-centrist alternative to the anti-abortion extremists who would have the government ban the practice and the pro-abortion extremists who would have the government actively promote it - then I suppose that yes, Democrats are going to look like the bigger-tent party.
In any case, the main point of my original post wasn't to argue that the Democrats are way more inflexible than the Republicans; it was just to highlight the Dems' inflexibility in the context of claims from figures like Douglas Kmiec that it's possible to advance a serious pro-life agenda within the Democratic tent. I don't think that there's really any pro-choice equivalent to the handwringing that regularly takes place among pro-life Catholics (and evangelicals, to a lesser extent) over whether they can legitimately vote Democratic, and it was that handwringing that I was addressing - by arguing that yes, pro-lifers can legitimately vote for Democrats, but that such a vote shouldn't be accompanied by self-deception about the compromises that it entails.