Actually, however, every soldier is taught that, as a matter of law, he must disobey orders that are unlawful. If he obeys such orders, he is subject to being criminally prosecuted.

What are examples of unlawful orders?

The recent World War II war movie Fury, starring Brad Pitt, provides one example. Pitt, who plays the role of a U.S. tank sergeant, orders one of his men to shoot a German soldier who has been taken prisoner. The man refuses to do so. Pitt forces the man to squeeze the trigger of the gun that is pointed at the POW. The prisoner is shot and killed.

Pitt is guilty of a war crime. He has broken the law by killing an enemy soldier who has been taken captive.

Consider the case of Army Lt. William F. Calley during the Vietnam War. Calley led his platoon into a Vietnamese village, where he and his platoon proceeded to kill hundreds of people, mostly elderly people, women, children, and infants.