The photojournalist who seems to me to be most skillful at explaining America's wars to Americans is Elliot D. Woods. As a former soldier, he presents the point of view of the combatants as few others can. However, he also seems able to achieve an extraordinary level of rapport with the people in whose lands the wars are being waged.
There is a great article with pictures and words by Woods in the March issue of The Sun magazine about a platoon of Marines in Afghanistan. It paints a terrible picture in black and white of bravery and futility. I haven't found an on line presentation of the article yet, but I'll post it here when I do. In the meantime, it is worth the effort to track down a copy of the magazine.