Here’s David Allen Green being correct, for the most part, on the resurgent issue of the death penalty.
In brief: capital punishment is impractical, inefficient, ineffective, and anti-humanist. It fails to do the things it ostensibly is intended to do. It is a bad means to a bad end.
I’m not completely with David on every aspect of his argument. I’m not sure who these “libertarians” (with his own “scare” quotes) in support of the death penalty are, with their apparently inconsistent vision of the state’s role in taking citizens’ lives. This certainly doesn’t sound like any formulation of libertarianism I’ve heard from people actually involved with that political group. [Edit 9/8/11: My commenters have started doing the actual research I didn’t bother with again: see below. A brief flit through the interwebs seems to indicate that libertarian thought on capital punishment is divided, although citation needed.]
And the deterrence argument isn’t quite as dismissable as he finds it. I’m not sure it even matters whether or not it promotes an injustice, if the claim that capital punishment deters other people from committing serious crimes isn’t even true. There are some complex questions raised in that link, but there’s certainly no good evidence that a deterrent effect does exist. If it did, presumably a competent application of statistics could demonstrate this, and then the necessity for “speculation about incidents which may never exist” could be annulled by actual data.
(I think the question is interesting enough to be worth asking: Could a deterrent effect be big enough to justify the death penalty? How much crime would it have to demonstrably prevent before it became a good idea for the state to take the lives of convicted murderers?)
But David is right that the orchestrated taking of a human life is simply a moral wrong on its own face.
Personally, as I think I’ve said before, I feel that being a humanist requires being completely opposed to all forms of retribution, i.e. making things worse so that they’ll be more “fair”.
If you can argue that killing somebody will make things better – that it’ll prevent similar crimes, or prevent recidivism more efficiently than incarceration, or will bring about good in some other way – then I’ll hear it. But so far it doesn’t look like the supporters of the death penalty have reality on their side.
See also Heresy Corner’s discussion on the British government’s new e-petitions website, and the reasons why public opinion on capital punishment is becoming a contemporary topic again.