Opponents of the death penalty claim that it does not deter murder. Their implicit argument is that if there is no deterrence, then there is no need for the death penalty. In today's Washington Post, Harvard Law professor Cass Sunstein and Wharton public policy professor Justin Wolfers argue that the data on deterrence is murky at best. However, they suggest that the constitutionality of the death penalty may indeed hang on the deterrence argument:
Why is the Supreme Court debating deterrence? A prominent line of reasoning, endorsed by several justices, holds that if capital punishment fails to deter crime, it serves no useful purpose and hence is cruel and unusual, violating the Eighth Amendment. This reasoning tracks public debate as well. While some favor the death penalty on retributive grounds, many others (including President Bush) argue that the only sound reason for capital punishment is to deter murder.
It would be nice if the death penalty caused some would-be murderers to back down, but I actually find the deterrence argument mostly beside the point. The reason to retain the death penalty is vengeance, or as more polite people put it, retribution.
Many libertarians are against the death penalty. They argue that the power to execute is just too dangerous to trust to the minions of the government. My esteemed reason colleague Jacob Sullum writing about the recent Supreme Court decision upholding the constitutionality of lethal injection, noted:
This strange fastidiousness about making murderers as comfortable as possible when we kill them suggests that capital punishment in this country is ultimately doomed.
It's not doomed because it violates the Eighth Amendment's prohibition of "cruel and unusual punishments," contrary to what Justice John Paul Stevens now seems to think. As Justices Antonin Scalia and Clarence Thomas point out in their concurring opinions, a penalty explicitly envisioned by the Constitution (which refers to capital cases and says the government may not take someone's life without due process) can hardly violate the Constitution.
No, capital punishment is doomed because most Americans, including many who ostensibly support it, are not truly at ease with the idea of killing a man in cold blood. On balance, that is probably a good thing.
Recently, I was talking with an Episcopal priest friend about the death penalty and she thought she was playing a moral trump when she argued that if I wouldn't pull the switch to execute someone, then I couldn't be for it. I was puzzled by this argument since I would have no problem, for example, with pulling the switch on the person who cold-bloodedly and intentionally killed my wife. That observation ended the discussion. One of the chief reasons for having the state execute is not to spare the feelings of the survivors of murder victims, but to disrupt the development of perpetual vendettas.
That being said, in the era of post-conviction exoneration through DNA testing, I have become much more uncomfortable about the possibility that an innocent person might be executed.