Why Not Kill "Mass Murderers"?

Damon Linker asks:

If abortion truly is what the pro-life movement says it is -- if it is the infliction of deadly violence against an innocent and defenseless human being -- then doesn't morality demand that pro-lifers act in any way they can to stop this violence? I mean, if I believed that a guy working in an office down the street was murdering innocent and defenseless human beings every day, and the governing authorities repeatedly refused to intervene on behalf of the victims, I might feel compelled to do something about it, perhaps even something unreasonable and irresponsible. Wouldn't you?

What interests me is why these groups target a late-term abortion doctor. By their logic, there is nothing worse in killing an eight month-old fetus than an eight-minute old one. By my logic - see The Conservative Soul - there is an intuitive reason to worry more about babies that are much more developed than an enbryo. But I can't see why Operation Rescue would believe that. I suppose it's better marketing, because the images are so gruesome. Dreher responds:

The answer, I think, has to do with prudence. We live in a society and a culture in which there is wide disagreement about the moral personhood of the unborn child (or, if you prefer, "fetus"). Taking another human life is the gravest crime imaginable. If one is prepared to do that, one had better believe that one has no other choice, and that the stakes are radically high. The consequences for introducing lawless violence into a society, even in a righteous cause, are unpredictable, and stands to bring about a worse evil than the evil the violence is designed to fight.