Phil Klay, as both a participant and a writer, has been thinking deeply about war for a long time. In his two acclaimed works of fiction, the book of short stories “Redeployment,” which won a 2014 National Book Award, and the novel “Missionaries” (2020), and in the nonfiction collection “Uncertain Ground: Citizenship in an Age of Endless, Invisible War” (2022), Klay has interrogated, to profound effect and with a deeply humane and moral sensibility, what war does to our hearts and minds, individually and collectively, here and abroad…