It is alright to kill in self-defense or in a just war, for example. I do not know if this is good theology, or even if it is good translation, but I believe it is sound moral reasoning. I believe that deadly force is justifiable in self-defense broadly construed and in just war construed a bit more narrowly than our ancestors were inclined to practice it. I deny, however, that capital punishment is a similarly justifiable form of killing. Just as individuals and nations have a right to kill in self-defense, it is argued, so does society.
Capital punishment is society's version of self-defense.
There are several things wrong with this argument. I believe these criticisms are sound and ought to be persuasive. Experience in the public arena has shown, however, that these three good arguments are not usually sufficient to convince the American public. We need a more compelling demonstration that capital punishment is importantly different from self-defense. I have found the following line of reasoning to have considerable impact in public debates and offer it to the philosophical community for criticism and development.