A famous saying has it that truth is the first casualty in any war. Not only do national leaders like to employ overblown rhetoric to justify their decisions to send troops into combat, but once the shooting begins, those who must pull the triggers or staff the home front seem to prefer heroic mythology to the reality of fire and death. Understanding this, war correspondents from Homer to Ernie Pyle have tended to rein in their normal skepticism, serving up instead what both the government and the public want to hear.
That tradition changed somewhat during the Vietnam War, with its...