"When the state kills those whose guilt is in serious doubt, or when the state kills those to whom it has not given fair justice, it doesn’t just perform an injustice upon the individual, the rule of law, and the Constitution. It also undermines the very legitimacy of the death penalty itself, for its continuing use as a sentencing option derives its civic and moral strength mostly from the fiction that it can be, and is, credibly and reliably imposed. Once our confidence in that credibility is shattered, as it should be now that Davis is gone, all that’s left of the death penalty is state-sponsored retribution and the hangman’s noose."