The platoon was, an American military official would assert years later, “raggedy.” On their tiny, remote base, in a restive sector of eastern Afghanistan at an increasingly violent time of the war, they were known to wear bandannas and cutoff T-shirts. Their crude observation post was inadequately secured, a military review later found. Their first platoon leader, and then their first platoon sergeant, were replaced relatively early in the deployment because of problems. But the unit — Second Platoon, Blackfoot Company in the First Battalion, 501st Regiment — might well have remained indistinguishable from scores of other Army platoons in...