Abortion Doctor's Life Ended By Pro-Life Extremist

I need a little help here...

What system of measurement is employed when a decision is made to end the life of a doctor who performs abortions? Obviously, pro-life advocates must assign a value to a human life that is greater than a mothers wish to bear any or more children. It must also be greater than any governing principles set forth by a society engaged in population control (likely fueled by economic necessity, food shortages, etc.) In short, it must be great.

A pro-lifer may argue that by murdering one doctor, hundreds of human lives are spared from an otherwise premature end. Let us boil the argument down to a single baby. Would a pro-life extremist murder one human being for the sake of another? If so, one human life apparently has more value than the other. How can that be? There must be some system of depreciation in the value of human life, given that the extremist is presumably unacquainted with the doctor on a personal level (which would indicate that their only connection is the topic of abortion) and the only discernible difference between the doctor and the baby is age (and possibly gender, which is another topic altogether). This idea effectively negates the romantic notion that human life is of inestimable value. Not only does it have a value, but it depreciates over time like an automobile. How depressing.

On the other hand, pro-choice advocates stress the need to provide a method of reversing the inevitable effects of human reproductive organs fulfilling the task to which they were ultimately designed for; to perpetuate the evolution of a species. Talk about going against the grain.

Maybe it's better that I don't try to make sense of a debate that has endured for centuries and remains a sore spot that even federal governments have difficulty grappling with.

In other words, don't ask me if I'm pro-life or pro-choice. I don't know. I don't have the world of facts necessary to make such a decision, and if I did, you probably wouldn't like the answer anyway :-) However, if you're fanatical about it and need to decide for yourself, here's a link to more information covering both sides of the issue:

http://en.wikipedia.org/wiki/Abortion_debate