Naseem was charged with denigrating the Koran and the Prophet Muhammad. Two years later, awaiting his bail hearing surrounded by police and lawyers, he was gunned down. Faisal Khan, a 15-year-old Pakistani, beams for selfies with lawyers and police. Thousands hail him in the streets as a “holy warrior.” His claim to adulation? Allegedly gunning down in open court an American accused of blasphemy, a capital crime in this Islamic republic. Khan is charged with murder, which also carries a death sentence. But while lawyers line up to defend him, the attorney for Tahir Naseem, the U.S. citizen, has gone...