Ross Douthat on teen pregnancy rates in blue states and red states:
If liberal social policies really led inexorably to fewer unplanned pregnancies and thus fewer abortions, you would expect "blue" regions of the country to have lower teen pregnancy rates and fewer abortions per capita than demographically similar "red" regions.
But that isn't what the data show. Instead, abortion rates are frequently higher in more liberal states, where access is often largely unrestricted, than in more conservative states, which are more likely to have parental consent laws, waiting periods, and so on. "Safe, legal and rare" is a nice slogan, but liberal policies don't always seem to deliver the "rare" part.
What’s more, another Guttmacher Institute study suggests that liberal states don’t necessarily do better than conservative ones at preventing teenagers from getting pregnant in the first place. Instead, the lower teenage birth rates in many blue states are mostly just a consequence of (again) their higher abortion rates. Liberal California, for instance, has a higher teen pregnancy rate than socially conservative Alabama; the Californian teenage birth rate is only lower because the Californian abortion rate is more than twice as high.
Are abortion rates lower in states that make it really hard to get an abortion? Of course. I'm not really clear on what, if anything, this is supposed to prove.
As for California and Alabama, that's mostly just a clever bit of cherry picking. The table below is reconstructed from Guttmacher Institute data, and it gives a better sense of the big picture. Douthat is right that there's not a sharp red-blue divide between states with the highest and lowest teen pregnancy rates. Still, the top 10 is pretty heavily dominated by red states and the bottom 10 is pretty heavily dominated by blue states. I think it's probably unwise to pretend that there are simple lessons to be derived from this, but at the same time it's deceptive to pretend that the divide isn't there. There really is a difference, and it's likely that social values play a role in it.