This is the story of a dinner party. It occurred in a suburban middle-class community — maybe slightly upscale middle class, but not much — just outside one of our big cities. Pretty typical place. The guests all knew each other. They were neighbors or friends or acquaintances who’d been to these parties many times. They were white, every one, mostly businessmen and their wives, and some engineers who work or once worked in the nearby defense industries. The postdinner conversation was the usual stuff — who’s moving in, who’s moving out. Anybody heard from Ralph since he moved to...