LAHORE, Pakistan — Umar Kundi was his parents’ pride, an ambitious young man from a small town who made it to medical school in the big city. It seemed like a story of working-class success, living proof in this unequal society that a telephone operator’s son could become a doctor. The New York Times Lahore has enduring social problems like chronic unemployment. But things went wrong along the way. On campus Mr. Kundi fell in with a hard-line Islamic group. His degree did not get him a job, and he drifted in the urban crush of young people looking for work. His early radicalization helped channel his ambitions in a grander, more sinister way. Instead of healing the sick,...