"Many that live deserve death. And some that die deserve life. Can you give it to them? Then be not too eager to deal out death in the name of justice, fearing for your own safety. Even the wise cannot see all ends."
Gandalf, The Fellowship of the Ring
Granted, when it comes to the question of capital punishment, those on death row tend in their character to be more like Gollum (for whom Frodo desires death in this Tolkien quote) than like Socrates faced with the hemlock in Jacques-Louis David's famous painting. And it is noteworthy as regards the quote that contemporary America endeavors to give (deserved) life to those fated to die every bit as aggressively as it seeks to give (deserved) death to those otherwise fated to live after committing heinous crimes. In this respect capital punishment is a grim mirror image of the out-of-control medical-industrial complex. Even the wise...
This came to mind after a recent local story in which the Supreme Court of North Carolina decided (4-3!) that the state medical board cannot in fact discipline physicians who participate in executions (i.e. by monitoring vital signs to insure that the inmate is "not suffering"). Death sentences, which had been on hold for a couple of years because of this question, can presumably start up again.
It took me years to decide where I came down on the question of the death penalty. I used to be for it, as I've always had a healthy respect for evil as a real force in the world, and as Tolkien wrote, in terms of abstract justice there are people who have done things so awful that they deserve to die. However, in an odd parallel to the question of the possible rationality of suicide, I think that the absoluteness of death precludes, in practice, the ethically justifiable intentional taking of life for any reason but direct and obvious self-defense (any society-wide deterrent effect of capital punishment is debated, and is definitely not direct and obvious).
Capital punishment, like suicide, is a declaration that this particular person's life cannot be considered worth living; in an execution the state effectively commits suicide on another's behalf, conflating vengeance and penance. In this sense it is richly ironic that those on death row are not permitted to commit suicide, and indeed may not be considered "competent" for execution if they are suicidal. Both execution and suicide are acts of dreadful certainty: "By the permanence of this act I affirm that I (or we, the state) cannot possibly be mistaken, that things could never come to be different, whether through additional evidence or altered perception." Playing God, indeed, although to do so with someone else's life is rather different, isn't it, than to do so with one's own?
What physician would want the job of monitoring an execution? I suppose it could be a deeply ethical act, inasmuch as the about-to-be-executed are, by definition, those who have had every human right stripped from them--except for the right to freedom from inflicted physical agony. Another irony, as Atul Gawande's recent New Yorker article painfully described, is the regular use of long-term solitary confinement, which arguably inflicts emotional distress far more horrific than the physical pain someone could undergo during lethal injection. What is the difference? Well, there are media and family representatives observing an execution, but in a solitary cell, not so much. Very discreet.
I always come back to Oliver Cromwell's (paraphrased) admonition, "I beseech you, in the bowels of Christ, consider that you may be mistaken." Suicide means blinding oneself to the possibility of the ultimate error. Execution leaves this possibility open, but removes the option of ever rectifying it. Eventually the civilized world will view capital punishment much in the way it views slavery, as beyond the pale (much of the world does already actually, we just haven't joined it yet).