"There’s a strong presumption that military orders are lawful," Lepper said. "That’s as it must be, because if the presumption ran the other way, our military would be hopelessly weakened."
In 1968, U.S. troops massacred hundreds of unarmed civilians in the Vietnamese village of My Lai, a crime their commanders initially tried to conceal. When the killings came to light, 1st Lt. William Calley was convicted of murder despite claiming he had been following orders — a case that taught generations of soldiers that some commands are so clearly criminal they must be refused.