When you're wounded and left on Afghanistan's plains,And the women come out to cut up what remains, Jest roll to your rifle and blow out your brains an' go to your Gawd like a soldier.

—Rudyard Kipling, 1879

The war against the Soviet Union will be such that it cannot be conducted in a knightly fashion; The struggle is one of ideologies and racial differences and will have to be conducted with unprecedented, unmerciful, and unrelenting harshness.

—Adolph Hitler

It isn’t easy to kill a man in cold blood…unless one is entirely heartless or, as I was, numb with fear

—Guy Sajer, The Forgotten Soldier

May God grant us victory because if they get their revenge, we’re in for a hard time

—Anonymous German Soldier

War inevitably involves killing. In peacetime, taking a person’s life is proscribed by societal taboos and laws. In battle, warriors are sanctioned to take lives within tightly controlled limits including the just war tradition, the laws of armed conflict, the rules of engagement, and other imposed restrictions. When these limits are violated, disciplined units take action against their own members to limit violence to what is permissible. The violent emotions unlocked by war, however, can violate the boundaries intended to limit violence. The chaos and disorder inherent to a battlefield give an opportunity to exceed the boundaries of what is permitted outside the observation of one’s unit, or one’s superiors. A unit may be collectively subject to strong emotions, discipline may break down and unit members may tolerate unjustified violence. Atrocity may also spring from a rational decision; a matter of convenience, for example, may be for a unit to kill prisoners to avoid being saddled with responsibilities of caring for them. At a higher level, commanders may demand unlawful violence (from “take no prisoners” to ordering genocide), creating major moral dilemmas for subordinates. Higher still, a significant complication is the lack of universally accepted standards, as one side’s interpretation of what is allowable is unlikely to match those of the adversary—these norms may vary as the balance of power tips, or the desperation of the situation grows.