The civilian can always say, "This is no place for me," and get up and walk away.

But the soldier cannot say that.

He and his officers, the Red Cross nurses, doctors, ambulance-bearers, and even the correspondents have taken some kind of oath or signed some kind of contract that makes it easier for them than for the civilian to stay on the job.

For them to go away would require more courage than to remain.
Indeed, although courage is so highly regarded, it seems to be of all virtues the most common.

In six wars, among men of nearly every race, color, religion, and training, I have seen but four men who failed to show courage.