[UPDATE: I have in considerable measure conceded error on this subject, thanks to some very cogent arguments by Mark Kleiman; see here for my explanation.]

I particularly like the involvement of the victims' relatives in the killing of the monster; I think that if he'd killed one of my relatives, I would have wanted to play a role in killing him. Also, though for many instances I would prefer less painful forms of execution, I am especially pleased that the killing — and, yes, I am happy to call it a killing, a perfectly proper term for a perfectly proper act — was a slow throttling, and was preceded by a flogging. The one thing that troubles me (besides the fact that the murderer could only be killed once) is that the accomplice was sentenced to only 15 years in prison, but perhaps there's a good explanation.

I am being perfectly serious, by the way. I like civilization, but some forms of savagery deserve to be met not just with cold, bloodless justice but with the deliberate infliction of pain, with cruel vengeance rather than with supposed humaneness or squeamishness. I think it slights the burning injustice of the murders, and the pain of the families, to react in any other way.

And, yes, I know this aligns me in this instance with the Iranian government — but even a stopped clock is right twice a day, and in this instance the Iranians are quite correct.

UPDATE: I should mention that such a punishment would probably violate the Cruel and Unusual Punishment Clause. I'm not an expert on the history of the clause, but my point is that the punishment is proper because it's cruel (i.e., because it involves the deliberate infliction of pain as part of the punishment), so it may well be unconstitutional. I would therefore endorse amending the Cruel and Unusual Punishment Clause to expressly exclude punishment for some sorts of mass murders.

Naturally, I don't expect this to happen any time soon; my point is about what should be the rule, not about what is the rule, or even what is the constitutionally permissible rule. I think the Bill of Rights is generally a great idea, but I don't think it's holy writ handed down from on high. Certain amendments to it may well be proper, though again I freely acknowledge that they'd be highly unlikely.

In any event, there's nothing unconstitutional about letting victims' relatives participate in the execution; it's only the use of cruel means that would require an amendment.

FURTHER UPDATE: Strange Doctrines writes:

I know what Volokh means. There's a part of me too that would desire to meet savagery with savagery.

But there's another part of me that knows my humanity would be substantially diminished did I indulge my phant'sy for revenge. . . .

I've often heard this argument, and I'm sure it's heartfelt. But I've just never found it persuasive. Why would my humanity be diminished by participating in the killing of a monster (he had sexually abused and then murdered at least about 20 children), or even by deliberately inflicting pain on him? It seems to me that this is the reaction to a natural, understandable, and laudable human impulse to avenge (even if in a ridiculously inadequate way) the abuse and death of so many innocents. Why shouldn't one say that our humanity is diminished if this monster is allowed to live on, or even to die a painless death, when his victims and their families endured unimaginable pain?

Naturally, people on the other side are likewise unpersuaded by my views; I can't prove the soundness of my position any more than (I think) the other side can prove the soundness of its. In this area, we quickly come down to moral intuitions and visceral reactions. And, who knows, perhaps mine are wrong. But mere appeals to my humanity just don't do much for me.

AND WHILE WE'RE AT IT, ANOTHER RESPONSE TO A COUNTERARGUMENT: A couple of people pointed out the risk of error; and it's always possible that we're going to convict the wrong man. That's a decent argument against the death penalty generally, though I'm not persuaded by it. And it's certainly a great argument for fixing problems that may increase the risk of wrongful conviction — locking up the wrong man for life isn't much better in my book than executing the wrong man, especially since the chances of exonerating the wrongfully convicted lifers are, I suspect, pretty low.

But I don't see it as much of an argument for a painless execution as opposed to a painful one, or an execution by anonymous bureaucrats rather than one in which the victims' relatives participate. It's something of an argument, and I do think that there should and probably would be a higher threshold of felt certainty required on the jurors' and perhaps even reviewing judges' parts, just as I suspect that in practice most jurors today require a higher level of certainty to vote for a death sentence than for other sentences. But it doesn't, in my view, carry the day against the counterargument outlined in my original post.

BACK TO THE FIRST UPDATE: Dan Glick writes:

I can only shake my head at the different ways that people view the world. Volokh doesn't even attempt to logically justify his opinion, other than by an appeal to 'justice', that disgustingly noble coating with which nature has covered our instinct for revenge. I challenge anyone to look at this picture and tell me that the Iranians are better people or a better society for punishing a man that way, no matter what his crimes.
I agree that this really does comes down to a fundamental difference in how people view the world. Mr. Glick, after all, doesn't "attempt to logically justify his opinion" either, other than by an appeal to what he finds "disgusting" and to what he sees as the pejorative term "revenge." It's a battle of moral axioms and visceral reactions.

So, look at the picture; read even the doubtless sanitized description of the facts; decide for yourself. I doubt that the Iranians are better or worse people or a better or worse society for punishing this man this way — serial killings are rare enough that I doubt the punishment of serial killers has much of an effect of the society. But I do think that the Iranians are in this one respect more just than those societies that let serial killers live, and even slightly more just than those who execute serial killers in a supposedly "humane" way.

STILL FURTHER UPDATE: Clayton Cramer and Maimon Schwarzschild disagree; I'm not persuaded, but I think their posts are thoughtful and eloquent statements of the contrary view.