Byron Black was recently executed in Tennessee. This is not your typical capital case, however, because the current local district attorney actually agreed with the defense that Mr. Black's death sentence should be commuted to life in prison. However, the Tennessee Attorney General then took over the appeal and pushed for execution anyway. It's a perfect example of the growing tension between local prosecutors and state officials—and what happens when they disagree on life-or-death decisions. These are questions that don't have easy answers: What's a prosecutor's duty when defending decades-old convictions? And how do we balance finality in the justice system with evolving legal standards?