The catch: That pro-lifers have to believe that they will not be able to get everything that they want politically, and must prioritize their goals.

I'm with you on this one, and it ties in with a point that I have used several times in discussions about abortion, regarding why pro-lifers have done such a poor job thus far of accomplishing their goals.

If a person truly believes that "life starts at conception" and that abortion is taking the life of a human being, a rational actor who values human life would take action to minimize the loss of life, correct? If the pro-life movement was doing this, they would be proposing options that would be palatable to a much greater portion of society than their current hard-line ideas, though it might still not be enough to get laws passed. They should be not just willing, but eager, to make concessions for rape and incest victims, and for cases in which the life of the mother is in danger. You can argue the slippery slope all you want, but the fact is, human beings are being killed (as they believe) while they stick to their guns.