On June 28, in the main courtroom of Charlottesville’s federal courthouse, U.S. Attorney Thomas T. Cullen rose to his feet. It had been nearly two years since white supremacists brawled with counterprotesters at a violence-filled rally nearby; now, standing still and stoic, the tall, lean Cullen addressed the court regarding the sentencing of James Fields Jr. At the rally in August 2017, Fields, 22, had driven his Dodge Challenger into a crowd of peaceful protesters, maiming many and killing one. Having been convicted on federal hate crimes charges, Fields deserved nothing less than life in prison, Cullen argued. From the...