I don’t think the comparison is quite apt. But it still poses an interesting dilemma.
If, say, I was a German during WWII, and if I saw Joseph Mengele on the street, would I be morally justified in gunning him down on the spot, no matter what? Well, probably not. First of all, it is, according to the CCC, the duty of the state to prosecute criminals after the fact, not mine. When I see Mengele on the street, he is not, then and there, killing a Jew. Perhaps he has repented. Perhaps he will do so before sending another Jew to his death. What he has done, when I see him walking on the street, is all in the past. It is up to the state, not to me, to make him pay for his past crimes. The fact that the state was not, at that moment, willing to punish him, does not confer on me the right to act as the civil authority.
When Tiller was killed, every crime he had done was all in the past at that moment. As we know, the state was not willing to prosecute him. But it was still the state’s function, not the killer’s, to make Tiller pay for his past crimes. Tiller was not, then and there, trying to kill a baby. It would have been reasonable to believe that sometime or other Tiller would probably kill again. But it was not a certainty, and he was not in the act of doing it.
But on the other hand, what if I see Mengele starting to put a poisonous IV into a man’s arm? I am morally free to prevent him from doing it and, depending on a number of things, may be morally obliged to do it, even to the point of using deadly force against him. In making my decision, I would also be obliged to consider the other obligations I have in life and the consequences to others if I kill Mengele in his “clinic”. If, due to the protection provided by the state to Mengele’s clinic, my chances of getting access to it in order to intervene at the right moment are remote, the whole question is just a theoretical exercise.
It may seem hypocritical to some that we do not invade clinics like Tiller’s to stop them in the act, even to the point of using deadly force. But while we might have an easier time of it than one might have had in trying to invade Mengele’s clinic at Auschwitz, we are quite unlikely to succeed in the effort. Those places are well-protected. Knowing that, and knowing the likely futility of it, and further knowing that we might not actually find the perps in the act, and further knowing the consequences it will have to others (e.g., our families go without support, others to whom I have merely talked are prosecuted as “co-conspirators”) the moral obligation to invade the clinics to stop the perps in the act recedes from the “real” and becomes a theoretical exercise.
Having said all of that, one has to ask oneself whether one would nevertheless gun down one who had killed his/her own child or grandchild, yet walked because the state would not prosecute him. I would like to think I wouldn’t, but I don’t know for sure that I wouldn’t.
Because of that personal uncertainty, I truly do have to face the fact that some lives are more important to me than others.
And finally, I have to admit to myself that I am sufficiently unempathetic to be unmoved by Tiller’s death. The world is better off without him.
Only God has the right to take the life of any of His creatures when He decides it.