The Morality of War and the Law of War

There is a general presumption that the law should be congruent with morality— that is, that the prohibitions and permissions in the law should correspond to the prohibitions and permissions of morality. And indeed in most areas of domestic law, and perhaps especially in the criminal law, the elements of the law do in general derive more or less directly from the requirements of morality. I will argue in this chapter, however, that this correspondence with morality does not and, at present, cannot hold in the case of the international law of war. For various reasons, largely pragmatic in nature, the law of war must be substantially divergent from the morality of war.1 Our understanding of the morality of war has for many centuries been shaped by a tradition of thought known as the theory of the just war. In its earliest manifestations in ancient and medieval thought, this theory emerged from a synthesis of Christian doctrine and a natural law conception of morality. Its tendency was to understand the morality of war as an adaptation to problems of group conflict of the moral principles governing relations among individuals and to see just warfare as a form of punishment for wrongdoing. Its concern was with a rather pure conception of right and wrong that made few concessions to pragmatic considerations and was unwilling to compromise matters of principle for the sake of considerations of consequences. During this classical phase in the history of the theory, the principles of the just war were quite different from the laws of war in their current form. Later, beginning in the sixteenth century but principally during the eighteenth and nineteenth centuries, some juridical writers, seeking to develop a workable account of the law of nations, began to argue for principles governing the practice of war that were more ‘realistic’ in character. These principles were formulated in ways that were more sensitive to pragmatic concerns. This shift in thinking about the normative dimensions of war helped to lay the groundwork for the development and institutionalization of the international law of war from the late nineteenth century to the present.