The second point has to do with issue of deterrent. I argued — and believe — that the deterrent argument as normally formulated is morally unsound as a rationale for the death penalty. But, after sleeping on it, I want to inject a bit more nuance into my position. I do think there is a valuable deterrent effect in this sense: I think that the death penalty affirms the moral order and gives people a sense that they are responsible for their actions. It heightens our awareness of the preciousness of life and the evil of murder. In that sense, I think the deterrent argument is good and valuable. But I don’t think the death penalty can be justified simply as a warning to others. I don’t think even this deterrent-effect alone justifies the death penalty, but I don’t think it’s a bad subsidiary argument.

Also, there is one other kind of deterrence that is undeniable. A murderer who is put to death cannot murder again.