Is innocence a "distraction"?

A few weeks ago, David Dow -- a law professor who is expert on death-penalty matters -- had a provocative opinion piece in the New York Times, "The End of Innocence," in which he suggested, among other things, that "innocence is a distraction" in the capital-punishment debate:

For too many years now, though, death penalty opponents have seized on the nightmare of executing an innocent man as a tactic to erode support for capital punishment in America.

Innocence is a distraction. Most people on death row are like Roger Coleman, not Paul House, which is to say that most people on death row did what the state said they did. But that does not mean they should be executed.

Focusing on innocence forces abolitionists into silence when a cause célèbre turns out to be guilty. When the DNA testing ordered by Gov. Mark Warner of Virginia proved that Mr. Coleman was a murderer, and a good liar besides, abolitionists wrung their hands about how to respond. They seemed sorry that he had been guilty after all.

I, too, am a death penalty opponent, but I was happy to learn that Mr. Coleman was a murderer. I was happy that the prosecutors would not have to live with the guilt of knowing that they sent an innocent man to death row.  . . .

As Justice Scalia has said elsewhere, of course we are going to execute innocent people if we have the death penalty. The criminal justice system is made up of human beings, and fallible beings make mistakes.

But perhaps that is a price society is willing to pay. If the death penalty is worth having, it might still be worth having, despite the occasional loss of innocent life.  . .

[We] ought to focus on the far more pervasive problem: that the machinery of death in America is lawless, and in carrying out death sentences, we violate our legal principles nearly all of the time.

Dow makes a good point, I think.  (I would probably not characterize the "machinery of death" in America as "lawless"; but, certainly, even putting aside moral objections to capital punishment, it is badly flawed.)  To be sure, any decent people will and must care about the accuracy of the results of its criminal-justice process.  At the same time, a decent people will and must accept the possibility -- indeed, the reality -- of error even in the context of a criminal-justice process that is morally justifiable.  It seems to me that the heart of the matter is whether it is wrong for the political authority to kill a human being, lawfully convicted of murder, as punishment for that matter.  And, as I have argued elsewhere --

[W]hat the public square needs from engaged Christians is a counter-cultural argument about the dignity and destiny of the human person. Such an argument could help our fellow citizens reach the right conclusion about what to do with convicted murderers not so much by dusting the usual arguments with God-talk as by challenging our culture to understand who and what these condemned persons are, and why it should make a difference.