Well, as Nuremberg made clear, "just following orders" is no defense. Everybody sould have a moral compass and cannot legally be made to do something that is patently illegal, we still have free will after all regardless of how young or impressionable a soldier is. I knew that killing innocents was wrong when I was 19, I would assume anyone raised in a Christian nation would know the same thing. I think that is a pretty fair assumption to make, don't you?