Is it better to fight fairly and risk higher casualties than to fight unfairly and thereby reduce casualties? I think many of us have the intuition that war nowadays, despite incurring many fewer casualties than wars past, is much more disturbing for the fact that killing (e.g., by dropping bombs) (1) is so easy and (2) typically does not allow opponents any real self-defense. Is there anything to be said for a fair fight in war, or should our sole moral object be to minimize overall casualties?

First, I would take issue with the claim that war nowadays causes many fewer casualties. While this may be true for soldiers in the armed forces of modern industrial societies, it is clearly not so for the civilian population or even for the soldiers in "third world" nations. The Vietnam War is a good example of what I mean. But if I understand the question, I think "fair fight" is definitely not an ethical requirement, though fighting a "just war" is. To see what I mean by this distinction, consider the ethics of launching a surprise attack. Though in a clear sense this isn't "fighting fair", my view is that if the cause is just and it helps to win the war, of course do it. However, there are moral rules about how to conduct war, and, say, targeting civilians in order to reduce casualties among one's own soldiers is a violation of those rules. As long as one is fighting a just war, and conducting it justly, I don't see that the notion of fighting fair is relevant. After all, war is not a sport.