Modern analytical just war theory starts with Michael Walzer's defense of key tenets of the laws of war in his Just and Unjust Wars. Walzer advocates noncombatant immunity, proportionality, and combatant equality: combatants in war must target only combatants; unintentional harms that they inflict on noncombatants must be proportionate to the military objective secured; and combatants who abide by these principles fight permissibly, regardless of their aims. In recent years, the revisionist school of just war theory, led by Jeff McMahan, has radically undermined Walzer's defense of these principles. This essay situates Walzer's and the revisionists’ arguments, before illustrating the disturbing vision of the morality of war that results from revisionist premises. It concludes by showing how broadly Walzerian conclusions can be defended using more reliable foundations.
Some dismiss the very idea of just war theory. Of those, some deny that morality applies in war; for others, morality always applies, everywhere, and it could never license the horrors of war. The first group are sometimes called realists, the second: pacifists. Just war theory seeks a middle path: to justify war, but also to limit it. Wherever there have been wars, lawyers, theologians, and philosophers have sought to walk this line. Though most commonly associated with the Christian tradition, different iterations of just war theory are part of every culture.1 In this essay, I will focus on contemporary just war theory in the works of Anglophone analytical philosophers: I’ll call this analytical just war theory. And I will focus on the debate between the most prominent contemporary just war theorist, Michael Walzer, and his critics. Narrower still, I will focus on one question in that debate: how ought we to fight?
The “ought” in that question is unqualified. Our topic is neither the laws of war nor a side’s rules of engagement. Our focus instead is on the categorical . . .
- 1For comprehensive historical sources, see Gregory M. Reichberg, Henrik Syse, and Endre Begby, The Ethics of War: Classic and Contemporary Readings (Oxford: Blackwell, 2006).