People tend to assume (I used to) that the legal debate about Roe v. Wade parallels the moral arguments about abortion and fetal personhood. We typically think that those who support the decision accept arguments like those of Mary Anne Warren or Judith Jarvis Thomson that abortion is justified, and opponents of the decision advance arguments like those of John Noonan, or Francis Beckwith, or Scott Klusendorf that fetuses are persons and therefore Roe has to be wrong.
Actually, the debate over Roe doesn't turn on that. This is my best reconstruction of it.
1. There is a constitutionally guaranteed right of privacy, of which we can be certain.
2. In the case of abortion, the right of privacy must prevail unless there is a countervailing right of which we can be certain, such as the fetus's right to life. This protects a woman's right to consult with her doctor and decide whether or not to get an abortion. Just as it is a violation of privacy rights to make birth control illegal, it violates privacy right to prohibit abortion, unless a countervailing right can be established.
3. But the fetus's right to life cannot be established. Reasonable persons can disagree as to whether fetuses have a right to life or not. One may, based on one's religion perhaps, believe that they have this right, but this right cannot be demonstrated in the same way that the right of privacy can be demonstrated.
4. Therefore there is a Constitutional right to abortion.
All attempts to oppose Roe that I know of, starting with the Rehnquist dissent when the original case was argued, argue not against 3 but against 1. Scalia in one interview refused to refer to himself as a pro-life justice. All he argued was that the right of privacy on which the decision as based was made an absolute when it should not be, and that therefore abortion should be a matter of democratic choice.
It seems you can accept the Roe argument even if you, in your own viewpoint, believe that fetuses have the right to life and that abortion is always wrong. The question is not whether abortion is justified, the question is whether the fetus's right to life is as evident as a woman's right to privacy.
Is the right to privacy really in doubt? If not, do arguments like the
SLED argument meet the requisite burden of proof? It would have to be so strong that it would be irrational to reject it.
See the discussion
here.