Overland, Gerhard, Ethics & International Affairs
A riddle in the ethics of war concerns whether lethal defensive force may be justifiably used against aggressing soldiers who are morally innocent. In this essay I argue that although there might be reasons for excusing soldiers as individuals, one may be justified in using defensive force against them provided that they have initiated threatening behavior and that our interpretation of that behavior as threatening is reasonable. I go on to investigate various implications of being in conflict with aggressing soldiers who are morally innocent, arguing that different restrictions apply to the use of defensive force when the aggressors cannot be held morally responsible for being aggressors.
My argument has important practical implications both for deciding whether to go to war and for deciding how to fight a just defensive war. Concerning the ongoing Iraq war, for example, it suggests that if it were only a matter of killing culpable members of the Republican Guard, invasion could perhaps have been justified. Since any attack would involve killing innocent conscripted soldiers as well as innocent civilians, however, there were good reasons to wait to see whether options other than intervening militarily would become available. If we are engaged in a just defensive war, my argument implies that we must accept a higher level of risk and more harm if we can assume that the aggressors are innocent rather than morally responsible for their harmful or threatening behavior.
The just war tradition is peculiar in that while its proponents think morality applies to war, they insist that soldiers from each side of a conflict may be justified in killing soldiers from the other side. (1) According to Michael Walzer, a central principle of war is that soldiers have an equal right to kill. (2) In becoming a soldier, one gains the right to kill other soldiers but loses one's immunity against being killed by soldiers of the opposing side. (3) That soldiers defending themselves and their state against unjust aggressors may permissibly have recourse to defensive force is not peculiar; the peculiarity is that, even when just war theory distinguishes between just and unjust sides in a war, it still grants equal rights to kill and liabilities to be killed to each individual soldier, regardless of which side he or she is on.
The implication of granting soldiers an equal right to kill is not immediately clear, however. It could be taken to mean either (or both) that they have a claim against others that they not be prevented from killing, or that they have a privilege to kill--that is, they have no duty not to fight with lethal means. (4) If we say that having a right to do X implies that others must not prevent the doing of X, it would imply that a soldier who is attempting to kill enemy soldiers has a claim against others, including those enemy soldiers, that he or she not be prevented from attempting this killing. But this implication is not very promising. We cannot seriously conceive of soldiers on opposing sides of a war as having parallel claims against each other that they each refrain from preventing the others' attempts to kill them.
Walzer may have had in mind the other element of having a right--namely, that by saying someone has a right to do X, it implies that the person has no duty not to do X. Saying that soldiers fighting an unjust war have a right to kill enemy soldiers could then be taken to mean that soldiers on the unjust side have no duty not to fight the unjust war and kill enemy soldiers. This may seem puzzling as well. It would imply that soldiers fighting for an unjust side have no duty not to kill other soldiers who justly defend themselves against the former's unjust aggression. Consider, as proposed by Jeff McMahan, an unjust combatant who knows that his country's aggressive war is unjust but who decides nonetheless to participate, perhaps because he prefers the risks of combat to the obloquy suffered by peaceniks in his society. …