What writers in our national literature have addressed the theme of war and the isolation and loneliness it brings?

So many American writers have touched on this theme in many different wars. The list below is by no means exhaustive but a sampling of some literature you could begin to examine with this theme:
The Sun Also Rises by Ernest Hemingway: Jake feels quite isolated after returning from World War I and has a difficult time as part of the "lost generation."
Two Soldiers by William Faulkner: This short story examines how war abroad can be isolating for those living at home, helplessly watching and listening for how war plays out.
E. E. Cummings: Cummings wrote both an autobiographical novel titled The Enormous Room about his experiences in World War I and poetry that reflects those themes. Consider this:

i would die etceterabravely of course my father usedto become hoarse talking about how it wasa privilege and if only hecould meanwhile my self etcetera lay quietlyin the deep mud et cetera(dreaming,etcetera, ofYour smileeyes knees and of your Etcetera)

The Red Badge of Courage by Stephen Crane: A young solider finds that war isn't filled with glory as he'd imagined and flees from a battle, causing much self-hatred and isolation.
Unbroken by Laura Hillenbrand: This more modern author recounts the struggle of physical isolation when a small group of soldiers survives a plane crash in the Pacific and is picked up by the Japanese in World War II.
Maus and Maus II by Art Spiegelman: Spiegelman immigrated to the United States when he was three years old and went on to tell the story of his father's struggles in World War II as a Jewish man in Europe. He does this through graphic novel format, showing both the isolation his father felt in the war and the isolation he feels toward and from his father because of the experiences of living in concentration camps.