In a post carrying the same headline as mine, Ed Morrissey apparently rejects the notion that proportionality is relevant to evaluating a war:
To use a crude analogy, if someone is stupid enought to bring a knife to a gunfight, it doesn't mean that those holding the guns have a moral obligation to fight with knives instead. Proportionality demands exactly that, and it leads to nothing but longer and more destructive wars.
It's not just Morrissey, of course. We've seen the same sort of thing from a lot of folks both in the blogosphere and the punditry.
In my view, however, this is a mischaraterization of the meaning of proportionality in this context. Proportionality in the jus ad bellum refers to the necessity for a correspondence between the injustice or wrong that serves as the casus belli and the likely humanitarian costs entailed in waging war. Proportionality in the jus in bello refers to the need to avoid using military force excessive to the accomplishment of the goal and, in particular, to the obligation to minimize collateral damage as much as possible. Neither would forbid you from bringing a gun to a kinfe fight, although they might well forbid bringing a tactical nuke to a street brawl.
But let's assume Morrissey is right about the meaning of proportionality, at least as it is being used in the present debate. Let's see just how far we're prepared to push that proposition.
In his wonderful book Three Men in a Boat, Jerome K. Jerome tells a story that might usefully serve as a parable about proportionality:
The narrarator and his friend Harris are boating on the Thames River and, over lunch, fall into a discussion of the growing tendency for Thames riverbank proprietors to put up notice boards banning boats from side creeks:
The selfishness of the riparian proprietor grows with every year. If these men had their way they would close the river Thames altogether. They actually do this along the minor tributary streams and in the backwaters. They drive posts into the bed of the stream, and draw chains across from bank to bank, and nail huge notice-boards on every tree. The sight of those notice-boards rouses every evil instinct in my nature. I feel I want to tear each one down, and hammer it over the head of the man who put it up, until I have killed him, and then I would bury him, and put the board up over the grave as a tombstone.
I mentioned these feelings of mine to Harris, and he said he had them worse than that. He said he not only felt he wanted to kill the man who caused the board to be put up, but that he should like to slaughter the whole of his family and all his friends and relations, and then burn down his house. This seemed to me to be going too far, and I said so to Harris; but he answered:
"Not a bit of it. Serve `em all jolly well right, and I'd go and sing comic songs on the ruins."
I was vexed to hear Harris go on in this blood-thirsty strain. We never ought to allow our instincts of justice to degenerate into mere vindictiveness. It was a long while before I could get Harris to take a more Christian view of the subject, but I succeeded at last, and he promised me that he would spare the friends and relations at all events, and would not sing comic songs on the ruins.
It's been said "that a good parable is like a window. We look through the parable and see things in a different way, and then at some point we catch our own reflection in the window." We can all see ourselves in Jerome's story, because we've all had similar reactions to various provocations.
What gives Jerome's story it's special relevance is the subtle implicit nod to Matthew 7:3-4 (Jerome was a deeply religious man):
Why do you see the speck that is in your brother's eye, but don't consider the beam that is in your own eye?
Or how will you tell your brother,'Let me remove the speck from your eye;' and behold, the beam is in your own eye?
You hypocrite! First remove the beam out of your own eye, and then you can see clearly to remove the speck out of your brother's eye.
The narrator recognizes that Harris has grossly overreacted. He knows that, however awful the behavior of the Thames riparian proprietors, this is hardly a case for slaughtering the friends and family (let alone singing comic songs on the ruins). Yet, the narrator has failed to recognize the splinter in his own eye - namely, his own desire to slaughter the proprietor.
The moral of the story thus is that a response needs to be proportionate to the offense. At least for those of us who are Catholics, this lesson applies to how war is waged just as much as to the situation in which Jerome's narrator and Harris found themselves. Catechism para. 2312 states: "The Church and human reason both assert the permanent validity of the moral law during armed conflict. 'The mere fact that war has regrettably broken out does not mean that everything becomes licit between the warring parties.'" As part of that moral law, proportionality is implied by para. 2309: "the use of arms must not produce evils and disorders graver than the evil to be eliminated. The power of modem means of destruction weighs very heavily in evaluating this condition."
This is indisputably part of the magisterial teaching of the church, not part of the proverbial cafeteria.
Reasonable people can disagree about whether or not the norm of proportionality has been violated in the current conflict. The notion that proportionality is irrelevant, however, strikes me as fundamentally misguided.
