Some of our smarter commenters beat me to this, but I still want to highlight it. This meditation by a young lieutenant, about one-third of the way through the book, and I think is its moral center. I don't think I have ever seen combat leadership defined quite as he does here in his second paragraph:
For us, violence was killing; there was no management involved. People were either dead, or they were not. I could not 'manage' my platoon up a hill. I had to lead them up there.
I had to do more than keep them alive. I had to preserve their human dignity. I was making them kill, forcing them to commit the most uncivilized of acts, but at the same time I had to keep them civilized. That was my duty as their leader. . . War gives the appearance of condoning almost everything, but men must live with their actions for a long time afterward. A leader has to help them understand that there are lines they must not cross. He is their link to normalcy, to order, to humanity. If the leader loses his own sense of propriety or shrinks from his duty, anything will be allowed.
. . . War is, at its very core, the absence of order; and the absence of order leads very easily to the absence of morality, unless the leader can preserve each of them in its place.
Thomas E. Ricks covered the U.S. military for the Washington Post from 2000 through 2008.