War's legitimacy and its fascination for us are both based on a belief that under certain circumstances, war is just and good. Every society defines this a bit differently; for many 19th century Americans involved in fighting Indians, murder, rape, and plunder were good; but in this essay, I intend to begin with the narrowest possible definition, the one definition so circumscribed that all human societies would agree that the actions it describes are just. I will then argue that they are not just and that a better way to live would involve defining all war as morally wrong.
Michael Walzer, in the opening words of his Just and Unjust Wars, states that
For as long as men and women have talked about war, they have talked about it in terms of right and wrong. And for almost as long, some among them have derided such talk, called it a charade, insisted that war lies beyond (or beneath) moral judgment. War is a world apart, where life itself is at stake, where human nature is reduced to its elemental forms, where self-interest and necessity prevail. Here men and women do what they must to save themselves and their communities, and morality and law have no place. Inter arma silent leges: in time of war the law is silent.
Where life itself is at stake. These words are at the heart of the thought, may be at the heart of all thought; they are the hard case, the exception to our system of morality. Do we not test all systems by how they handle the hard cases? We are always saying that the proof of the robustness of a system of free expression is how it handles hate speech, pornography or other unpopular speech, not how it handles the speech we approve of. Similarly, the test of any system of moral rules is how it handles war. We beg the question by saying that war, or anything else, lies "beyond" moral rules. What we are then really saying is that we choose to make none to cover this sphere of human activity, or to suspend the ones we have made. In either case, a human choice was made, a fact that is glossed over when we say that war lies "beyond" or "above" our morality.
We glorify a moral rule "Thou shalt not kill", but easily allow a battlefield exception. What variable allows the same act to be wrong on Main Street but right on the beaches of Normandy, at Dien Bien Phu, or in the skies of Iraq? There are a few possibilities.
If we analyze the sentence, "It is wrong to kill a man," we can evade the rule it states if battlefield killing is not really "killing" or the victim is not a "man". Both of these rationalizations are regularly used to argue that war is acceptable; it is characterized as "self-defense" or the enemy is demonized and not really considered human. The structure of the sentence allows us to get out of its stricture if we are not killing or the victim isn't human, but otherwise will not allow us to vary the word "wrong" without adding more words to the sentence. Thus, we might say, "It is wrong to kill a man unless I tell you to," which is an internally consistent statement, but hardly a system of morality. Yet this is exactly what our government says to us when it states that a declaration of war-- which is quite simply what it purports to be, a declaration-- can operate in any way to suspend moral rules.
So we have to continue looking for the explanation. Perhaps the sentence we are looking for is really, "It is wrong to kill a man, unless in self-defense." And in fact this is really the narrowest, in fact the kindest, justification for war, that a just war is really an act of self-defense against an aggressor. But here we are arguing necessity, and then strangely arguing that whatever is necessary is also moral. But this argument breaks down because actions which we take by choice are never by definition necessary. Someone may put you in a position where it is "necessary" to kill him in order for you to live, but you nevertheless had a choice: you could have chosen to die. I am not arguing that anyone is required to choose death to be a better human being. I am merely arguing that the choice to end the other's life to preserve yours is a practical choice but not a moral one.
The best illustration I can think of is the lifeboat. You are starving in a lifeboat with one other individual, who is very weak, and between you there is one crust of bread left. If you give it to him, you will die. If you break it in half, it is too little to sustain either of you, and you will both die. If you consume it, he will die, but you will live another day and perhaps be rescued. If you eat the crust of bread, was your act "necessary"? If it was necessary, was it "moral"?
If you answered yes to either question, especially the second one, you are on a slippery slope. What is the difference between this scenario and one in which you kill the other individual in order to maximize the available resources (eg, the boat is shaky and will more likely capsize with two than with one)? And what is the difference between the latter and the next scenario, in which you kill the other and consume his flesh in order to survive? Now we have gone so far down the slope that most people might suddenly discover, in thinking this through, that morality does obligate us to die sometimes. If eating your companion as the only means of survival is not acceptable, then society clearly expects you to die instead.
If necessity is never in itself sufficient to establish the morality of an action, then we must rethink the whole meaning and source of moral rules. Morality itself implies choices; if we necessarily had to exist in a particular fashion, it would not be meaningful to call that way of living moral. For example, the fact that we adhere to the ground when we walk, and do not fly off into outer space, is a physical phenomenon, not the result of adhering to a moral rule. If the necessity of gravity is not enough to create morality, then the necessity of killing certainly would not do so either. When we say something was necessary, whether or not we then call it moral as a result, we are using a vocabulary designed to evade moral analysis. Choices can be analyzed, but necessary actions are not choices; we may choose to obey the traffic laws, but we do not choose to obey the law of gravity. It is a very common phenomenon to call something necessary which is actually a choice, so as to evade the implication that we have done something which can be analyzed for its adherence to, or violation of, moral rules.
Conversely, necessity might be seen as relieving us of moral responsibility, rather than as itself being a higher good. If despite my best efforts, I lose control of my aircraft and it falls on top of someone through no fault of my own, necessity absolves me of the charge of manslaughter. Once the meteorite severed the fuel line, it was necessary, not my choice, that I fall.
Lets start by putting aside the insight that law and morality are not coextensive and should not be. Not every sin is punishable by law, and conversely, not every excuse that absolves us legally should absolve us morally. I may be acquitted of a crime, yet stand guilty of a shameful act. Arguments from necessity and self-defense therefore go astray by attempting to carry concepts with which the law alone is comfortable into the moral field, where frequently they do not fit.
Suppose we formed a community in which, by mutual agreement, all violence was shameful, even if legally excused by self-defense. Suppose that we really took this to an extreme, and held that anyone found not guilty of a killing in self-defense nevertheless had to spend a year in the desert, doing penance, before being re-admitted to the community. My argument is that a community which followed this rule would be a better place to live than the one in which we exist, and which believes that violence in war and under certain other conditions is an ennobling experience. There would be less violence, and warriors would only go to war if they were convinced of the justice of the cause and nevertheless willing to do the required penance afterwards.
The only argument I can imagine against such a society is that it would not survive an evolutionary contest against more ruthless killers. I am not convinced this is true. As I have written elsewhere, optimism even to the point of self-deception is the cornerstone of any moral system; without the confidence that there can be something better, we live in the Hobbesian world of all against all. If we believe that a people who held all violence shameful would be killed, then we have placed ourselves on the road to becoming the opposite: the strongest, most ruthless killers in the place. For there is always a killer somewhere in the equation, and if we are too frightened of him, then we must ourselves become a better killer, so we can kill him. Doing so, we may perhaps plead necessity, but we should not fool ourselves that we have acted morally or even that we have not made choices.