I have an idealistic temperament so I understand the noble aspirations of many "righteous" causes that have led mankind to war over the ages. Leaving aside the more cynical aspects of many of those causes for now, there is no doubt that war rarely meets the idealism of any participant, no matter how noble.
At its bare-boned essence, war is death. And I'm not sure which would be worse, my own death or the burden of causing the death of others. I'd like to think it's the latter.
The story is based on Salinger's own experiences in WWII. Salinger may have had his own issues "keeping his faculties intact" leading to withdrawal from the world after his writing fame proved to much for him. The story hints at those issues in the "squalor" section.
Salinger also had a fascination with youth, as should by obvious with his most famous literary character, Holden Caulfied. For myself, I never liked Catcher in the Rye. Maybe it was the whole prep school thing. But I oddly identified with his soldier, first-person narrator in Esmé. And in my teens I ruled out a military career, easy to do in the era of post-Vietnam demobilization.
The story has the narrator while in England training for D-Day visit the village church where he hears a children's choir rehearsing. Later in a tea shop, he meets the girl he had been watching in the choir, a precocious 13-year-old. She and her annoying little brother strike up a friendship with him. The children's father had already been killed in the war. Esmé, learning the soldier fancied himself as a writer, asks him to write her a story.
"It doesn't have to be terribly prolific! Just so that it isn't childish and silly." She reflected. "I prefer stories about squalor."
"About what?" I said, leaning forward.
"Squalor. I'm extremely interested in squalor."After leaving, she comes back in the tea shop so her brother could say 'goodbye' (and finish his joke.)
"You're quite sure you won't forget to write that story for me?" she asked. "It doesn't have to be exclusively for me. It can-"
I said there was absolutely no chance that I'd forget. I told her that I'd never written a story for anybody, but that it seemed like exactly the right time to get down to it.
She nodded. "Make it extremely squalid and moving," she suggested. "Are you at all acquainted with squalor?"
I said not exactly but that I was getting better acquainted with it, in one form or another, all the time, and that I'd do my best to come up to her specifications. We shook hands.
"Isn't it a pity that we didn't meet under less extenuating circumstances?"
I said it was, I said it certainly was.
"Goodbye," Esmé said. "I hope you return from the war with all your faculties intact."I won't go into "the squalid, or moving, part of the story." I encourage you to read it yourself. The effect it had on me to to avoid war and military service in an attempt to keep my own faculties intact. I pray the whole world would do the same.