Amit Ghate at Thrutch has a post on the proportionality doctrine now found in the "Just War" theory of warfare. This doctrine holds that the proper response to an aggressor is to inflict on him an amount of harm that is commensurate to the harm he inflicted on you. Or, that which you hope to gain by retaliation cannot exceed the damage done to you.
Of course this is a notion that is irrational in the extreme. As far as I can tell, proportionality is a concept of measurement and as such has no value outside that which is being measured or proportioned. Proportionality could be a very evil and dangerous thing.
For example, you are attacked by a virus and become ill. You go to a doctor and he identifies the virus. But then he tells you that he is not going to give you enough vaccine to kill the virus and return you to health. Instead, because he believes in proportionality, he is only going to give you enough vaccine to make the virus as sick as you are.
What would you think about that? Would you want this doctor to draw up your family health plan? Would you want to see doctors with this kind of thinking in charge of world health? And what do you think would happen to world health if they were?
Happily, we don't have such doctors in charge of world health--yet. Unfortunately, we have exactly those kinds of people and ideas in charge of America's military policy. And that is why cheap little thugs all around the world are attacking and challenging America daily--because they have nothing to fear.
There are a lot of things wrong with that nonsensical notion. Ayn Rand once advised us not to waste time examining a folly, but to ask what is it designed to accomplish?
Well, if you have a population of 100 and so does an aggressor, and he attacks you killing 10 of your people and you retaliate killing 10 of his people, and back and forth, you will wind up with 0 people and he will still have ten left. He wins. You lose.
Proportionality is a doctrine of, by and for aggressors. If an aggressor wanted to attack a neighbor, how could he do it proportionally? Proportional to what? It's impossible to apply the concept to an aggressor. Thus proportionality is a concept designed to be applied only to the retaliatory use of force. It is a straight jacket placed on the attacked nation's right of self defense.
That is what 'proportionality' is designed to accomplish.
The proper response in the above example would be to retaliate not by trying to kill just 10 of his people but to destroy his ability to fight and his population's will to fight. It is never enough to try and destroy just his ability to fight. If the will is not destroyed, the population will find ways to keep fighting. If you destroy their will to fight, their ability to fight will evaporate.
An overwhelming first response in retaliation would be the proper response. You would have 90% of your population left and he would have more than 10 percent. Such a policy of overwhelming force is both the practical and moral thing to do. For their identification of this principle, I highly recommend the essay "Just War Theory and American Self Defense by Yaron Brook and Alex Epstein here. (Hat tip the Objective Standard)