When it does come to a member of a rifle company in the front line, it is almost impossible to make him stay there and do his duty. His motivation has to be internal. Comradeship is by far the strongest motivator—not wanting to let his buddies down, in the positive sense, not wanting to appear a coward in front of the men he loves and respects above all others in the negative sense. Discipline won’t do it, because discipline relies on punishment, and there is no punishment the Army can inflict on a front-line soldier worse than putting him into the front line.
