Child advocates, former prosecutors, mental health professionals, former jury members, and the victim’s widow are asking for clemency for a survivor of child sexual abuse who killed his abuser and is scheduled to be executed October 3. Terrance “Terry” Williams was raised by a physically violent mother and was first raped at the age of 6, before being raped repeatedly by his school teacher. As a teenager, he was sexually abused by two adult men, one of whom used his position as a church leader to prey on teenagers and boys. Three months after turning 18, Terry killed one of his abusers, the day after he had raped him.

But the jury had no idea about this abuse. Terry was ...