The Brown University shooting in Rhode Island is more than a crime scene; it is a deep tear in the fabric of a community that believed, as most campuses do, that it was at least somewhat insulated from the worst of the world. Two students were killed, several others were injured, and a campus that once buzzed with end-of-semester stress is now soaked in a kind of disbelief that does not easily fade. The gunman is still at large, and no one knows why this happened. That not knowing sits in the...