From the apathetic reaction to atrocities committed in Vietnam by the United States and its allies, one may conclude that moral restrictions on the conduct of war command almost as little sympathy among the general public as they do among those charged with the formation of U.S. military policy. Even when restrictions on the conduct of warfare are defended, it is usually on legal grounds alone: their moral basis is often poorly understood. I wish to argue that certain restrictions are neither arbitrary nor merely conventional, and that their validity does not depend simply on their usefulness. There is, in other words, a moral basis for the rules of war, even though the conventions now officially in force are far from giving it perfect expression.

No elaborate moral theory is required to account for what is wrong in cases like the Mylai massacre, since it did not serve, and was not intended to serve, any strategic purpose. Moreover, if the participation of the United States in the Indo-Chinese war is entirely wrong to begin with, then that engagement is incapable of providing a justification for any measures taken in its pursuit – not only for the measures which are atrocities in every war, however just its aims.