 Of course, this is precisely the kind of nuance that would be disastrous if implemented in international law or if internalized as a norm by combatants. Weighing lives in war is informationally incredibly demanding. Soldiers need a principle they can apply. Discrimination is that principle. It is not merely a rule of thumb, since it entails something that is morally grounded—killing civilians is worse than killing soldiers. But it is also a rule of thumb, because it draws a starker contrast between intended and unintended killing than is intrinsically morally justified.