CENTENNIAL TRIBUTE ESSAY: A Theory of the Laws of War

The laws of war govern the weapons and tactics used by militaries during times of war. These laws, like other international laws, are not enforced by a central authority, but have force, if they do, only to the extent that nations either retaliate against belligerents who violate them or treat the laws of war as interior constraints. Whether the laws of war do have such force is a question that has not been answered. States frequently violate the laws of war, and when they do not, it is often because the laws have minimal, and controversial, content. 1 But states do take trouble because of these laws: They take the trouble to negotiate the laws of war during interwar conferences, and they take the trouble to argue during war that their behavior does not violate the laws of war. Putting aside the issue of how much the laws of war influence the behavior of states, a question of interest is why the laws of war have their particular content: why nations have agreed to the existing rules rather than some alternative set of rules. This question is the focus of this Essay. I will argue that the laws of war are best understood as devices for limiting the efficiency of military technology, understood broadly to include weapons and tactics that enjoy a high ratio of predatory impact to cost. The lower the level of military technology, the less wealth that nations will invest in conflict, ...