Professor B provides some useful data about late-term abortions in light of Obama's dumb (and I guess now clumsily partially retracted) comments about abortion policy. Admittedly, the policy consequences of what Obama is proposing would probably be negligible; as long as the decision rests with individual doctors rather than a panel, the precise definition of a health exemption makes very little difference on the ground. (Pre-Roe, some states with very strict-sounding statutes had relatively easy access to abortion in practice, while other state with broader access on paper had limited access in practice.) Of course, this cuts both ways: because most women don't choose to get post-viability abortions and most doctors won't perform them, there's no "problem" that needs to be solved here by changing the law.
So as Jill, Amanda, and Jan Crawford Greenburg point out, the problem with Obama's statement isn't so much a policy issue as that it plays into right-wing frames about the abortion issue. As Greenburg notes:
History shows that those proposals — offered and embraced by legislators who would call themselves "pro-choice" — have been seized by conservatives who oppose abortion. As Dailard wrote, the attacks on the mental health exception have had "significant repercussions beyond that significant issue, seriously reviving a legislative attack on abortion rights that largely has been dormant for two decades."
Given the unpopularity of the Republican position of banning pre-viability abortions, it's obviously in their interest to focus on the tiny minority of (already restricted) post-viability abortions, and pretend that women routinely seek them for frivolous reasons. The appropriate Democratic response is to note that the vast majority of abortions are pre-viability and there's no reason to believe that the laws restricting the tiny fraction of post-viability abortions don't work. The Democrats have to stop playing on Republican turf, and Obama's comments show that he doesn't seem to understand that. As with foreign policy, but with even less reason, national Democratic politicians seem to think that the Permanent Defensive Crouch is the way to go.
And since this isn't the only place I've seen the conflation, I suppose I should note yet again that bans on "partial birth" abortion apply to some pre-viability abortions and don't prevent any abortions at any stage of gestation from being performed. Instead they require doctors to perform abortions with methods that aren't as safe. And hence, not only do such bans have nothing to do with restricting post-viability abortion, they are facially irrational.