Hitch connects the dots:

Thus, as I was going on to argue, there is no reason to suppose that the death penalty is a deterrent. And then it hit me. I had been hammering on an open door. Nobody had been bothering to argue that the rope or the firing squad, or the gas chamber, or “Old Sparky” the bristle-making chair, or the deadly catheter were a deterrent. The point of the penalty was that it was death. It expressed righteous revulsion and symbolized rectitude and retribution. Voila tout!The reason why the United States is alone among comparable countries in its commitment to doing this is that it is the most religious of those countries. (Take away only China, which is run by a very nervous oligarchy, and the remaining death-penalty states in the world will generally be noticeable as theocratic ones.)

Once we clear away the brush, then, we can see the crystalline purity of the lex talionis and the principle of an eye for an eye. (You might wish to look up the chapter of Exodus in which that stipulation occurs: it is as close to sheer insane ranting and wicked babble as might well be wished, and features the famous ox-goring and witch-burning code on which, one sometimes fears, too much of humanity has been staked.)

Read the entire piece at Lapham’s Quarterly.