Here’s another argument against it: Even if there’s a case where there’s absolute certainty that the condemned is guilty, the execution still requires an executioner. Insofar as in individual takes on that role, he does damage to himself. (It’s no accident that firing squads are organized so that no one knows who fired the fatal shot.) And insofar as the executioner acts on behalf of society generally, he undermines that most crucial moral norm, the inviolability or sanctity of life.
This punishment isn’t worth the costs it imposes on us.
So let’s bring back the guillotine—and once it forces us to confront the barbarity of needlessly killing people who pose no threat to us, let’s abolish the death penalty. Countries without the death penalty get along just fine, and I don’t think Americans will be able to stomach it once they look it squarely in the face.