If you want a reason why an abortion compromise isn't possible, try this contrast: My idea of a plausible middle ground on the issue requires the overturning of Roe v. Wade, followed by a move toward a system in which abortion is legal but discouraged in, say, the first ten weeks of pregnancy, and basically illegal thereafter. Whereas Will Saletan and Freddie De Boer, both serious-minded pro-choicers, are convinced that a plausible middle ground would involve pragmatic pro-lifers throwing their support (and tax dollars) behind America's largest abortion provider, on the grounds that its commitment to preventing unplanned pregnancy makes Planned Parenthood "the most effective pro-life organization in the history of the world."
There are two things to be said about the latter notion, beyond what I said in my last post (and what John Schwenkler has to say here and here and here). The first is that just because it seems intuitive - to liberals, at least - that Planned Parenthood's efforts at making contraception available and affordable dramatically reduce the abortion rate doesn't necessarily make it so. Here I'd refer you to the extended, years-old argument between Megan (then "Jane Galt," of course) and Peter Northrup on contraception and abortion: Suffice it to say that the link between the availability of Planned Parenthood's services and the abortion rate is, well, non-obvious at best. Indeed, a quick gloss on the state-level data from the 1990s that Megan cited in her debate with Northrup would seem to suggest that the best way to reduce your abortion rate is to straightforwardly make abortions harder to get, through legal restrictions and cultural pressure. After all, liberal, well-off, Planned Parenthood-friendly Massachusetts, had a late-'90s abortion rate roughly twice as high as poor, socially-conservative states like Mississippi, Arkansas and Alabama, and more than three times as high as highly pro-life states like South Dakota and Utah.