Abortion is the tool for concealing rape and incest, and this is established through the lawsuits that planned unparenthood is losing, the 800 audio tracks from Life Dynamics and the many videos from Live Action Films.
Possibly the republican establishment sees utility in the availability of abortion in their own lives, if the exceptions for rape and incest remain. Conservatives, including myself, are walking away from the republicans, and now they have the teaparty. Meanwhile, the number of people calling themselves pro-life is growing.
People will come realize that increased abortion availability has led to increased rape "availability" and will let go of those abortion exceptions.