On September 17, 1998, Jack Kevorkian killed Thomas Youk by injecting him with a lethal combination of drugs. Houk was suffering from amyotrophic lateral sclerosis (Lou Gehrig’s disease), a terminal illness that causes gradual paralysis. According to his family, Houk was suffering from pain and fear of choking on his own saliva, and he wanted to end his suffering by ending his life. “I don’t want to die,” his brother later quoted him as saying, “but I don’t want to live like this.” Kevorkian’s act of euthanasia or “mercy killing” on Houk was videotaped and later broadcast to millions of Americans in a November 1998 episode of the venerable television newsmagazine “60 Minutes.”

The videotaped killing was the latest of many controversial writings and actions by Kevorkian, a retired pathologist...