"For decades, pro-life activists have been in the business of winning hearts and minds to their cause. Powerful arguments about the humanity of the unborn have moved public opinion, and a pro-life political force has made ambitious politicians feel the heat, whether or not they see the light. Pro-lifers' faith in the power of persuasion has been rewarded, and their political clout increased, by important converts, including Presidents Ronald Reagan and George W. Bush. Mitt Romney has also changed his position on abortion, but some social conservatives argue that membership in their ranks should be closed to this most recent...