On August 18, 1989, a middle-aged man in Georgia named Troy Davis attended a pool party before leaving with his friend Darrell Collins. An hour after midnight, Officer Mark MacPhail died from one gunshot to the head and another to the heart. Witnesses later placed Davis at the scene of the crime. Davis was sentenced with the death penalty. On the night of Wednesday, Sept. 21, Davis was executed with lethal injection.

Forget about the debate over whether the death penalty as a whole is just or not. The issue at heart here is the death penalty’s application. As Benjamin Franklin once said, “It is better one hundred guilty persons should escape than one innocent person should suffer.” In other words, the ultimate goal of a criminal justice system is to protect the innocent, to make sure those who have not committed crimes don’t face undue punishment. A justice system fails when an innocent is convicted. This is what may have happened with Troy Davis.

Since the trial and multiple appeals, seven of nine witnesses have recanted or drastically changed their original testimonies, saying they were pressured by the police to implicate Davis in the murder. No DNA evidence has shown Davis killed Officer MacPhail. No weapon was ever recovered.

Although we may never find out whether Davis killed MacPhail, the amount of doubt surrounding Davis’s case alone was enough justification to grant Davis clemency. Once we take someone’s life away through execution, we can’t give it back, even if we later find the person to be innocent. Death penalties should only be given out when we are absolutely certain the person committed the crime. The conviction and execution of Davis destroyed this moral rule, and represents the desecration of the very principle of justice. If Davis didn’t kill MacPhail, we, as a nation, may have collectively murdered an innocent man.

Now, it’s too late.