For almost four years, residents of El Paso waited for the gunman in the Walmart shooting to be sentenced. Twenty-three people—children, mothers, fathers, and grandparents—were murdered by a man who, according to the Department of Justice, described himself as a “white nationalist, motivated to kill Hispanics.” In the course of two days in July, their relatives took the stand at the gunman’s sentencing hearing. Francisco Rodriguez, the father of Javier Amir—the youngest of the victims, who died at fifteen—wore a necklace from which a miniature soccer ball hung. In it were some of the ashes of his son, who practiced the sport religiously at Horizon High School, where he had been a rising sophomore. “I carry his ashes everywhere I go,” Rodriguez said, eliciting quiet sobs from the audience....