Abortion and exceptions for the hard cases
Last week at Slate, an article purported to explain "why the anti-abortion movement stopped making allowances for rape and incest." Let me clear something up: I have been active in the anti-abortion movement for 22 years. The movement itself has never made exceptions for rape and incest. Certain politicians have, but the movement does not. The mainstream anti-abortion organizations such as National Right to Life and the American Life League oppose these exceptions and have opposed them for decades.
What Slate is doing is conflating the compromise of politicians with the stance of the anti-abortion movement itself. This is an understandable mistake (the politicians are the ones passing the laws, after all) but it is nonetheless an inaccurate representation of the anti-abortion movement.
Now, on to the issue itself. There is no scientifically credible argument that the fetus is not a human life. That is settled science. The basic question, then, is whether the fetus is a human person, and should therefore have all of the legal rights of someone already born. Is killing a fetus morally equivalent to killing someone who is five, ten or thirty years old? The anti-abortion movement's answer to that question is "yes."
If the fetus is a person, it is illogical to allow her to be killed because of her father's crimes. Certainly, the crime of rape is a horrific thing and traumatic mentally and physically for the victim. In a perfect world, rapists would face the death penalty, but his offspring should not face the same penalty.
"Is the fetus a human person" is the crux of the issue. It is clear that many of the people arguing most aggressively for exceptions for the "hard cases" do not actually believe the fetus is a person. Therefore, they do not have a frame of reference to understand why the anti-abortion movement (and consistently pro-life legislators) would not allow for an exception. You cannot understand the logic behind the argument if you do not understand the premise of that argument.