Mark Kleiman's post, which has persuaded me to change my views on the advisability of deliberately painful executions also has an excellent discussion of retribution as a goal of punishment. Mark points out that many recent blog posts have argued that retribution -- as opposed to just deterrence, incapacitation, and rehabilitation -- is simply not a legitimate goal of punishment.
Usually the arguments are cast as deprecating "revenge," "vengeance," and the like, and by their nature they are not limited to criticizing deliberately painful executions: They would apply equally to normal executions as well as prison sentences, if the purpose of the sentence is retribution (again, as opposed to the utilitarian purposes of deterrence, incapacitation, or rehabilitation).
Here I've agreed with Mark all along: It seems to me that retribution is a fundamental and entirely morally proper goal of punishment; and deriding it as some atavistic desire for vengeance is a mistake. It is a desire for vengeance, it is indeed psychologically deep-seated, but it is entirely just. Mark makes many excellent observations about this -- read his whole post -- but let me just quote the conclusion:
[V]indication of the victim and the expression of social disapproval of the act both strike me as perfectly sound reasons for punishment, independent of its function in controlling crime. . . .
Perhaps you disagree; if so, you're in the majority, in Blogland though not in the larger world. But if you disagree, then . . . could you explain to me why we kept chasing Nazi war criminals well into the 1990s? Was the Third Reich likely to come back? Were we hoping to deter the next round of mass murderers?
Or if the Nazis are too special a case to deal with, what is the deterrent and incapacitative justification for pursuing Augusto Pinochet? Isn't it obvious that Pinochet's victims deserve to have it shown to the world that what he and his goons did to them wasn't all right?
I think there are only three possible answers to these questions:
(1) We should punish the old Nazis and others, but only because this punishment will indeed "deter the next round of mass murderers." I think this argument is factually extraordinarily implausible -- future Nazis will expect to win the war, though they may realize that they'll die while losing the war, or get executed by outraged enemies shortly after they lose the war. The prospect of possibly being tracked down when in their 60s will be so remote that it will have next to no deterrent effect on their current decisions. That's why I think that these "maybe it'll deter people, but no no no we aren't trying to just exact retribution against them" arguments are usually just a cover for a desire for retribution.
(2) No point in going after these people. They're geezers who aren't going to hurt anyone; let them be.
(3) Track them down and punish them harshly (whether this includes execution, as with Eichmann, or not), because vengeance is morally proper, and perhaps even a moral imperative.
I'm with Mark in favor of #3.