The Washington Post notes that a series of studies are confirming that the death penalty does have a deterrent effect on crime:
“Science does really draw a conclusion. It did. There is no question about it,” said Naci Mocan, an economics professor at the University of Colorado at Denver. “The conclusion is there is a deterrent effect.”
A 2003 study he co-authored, and a 2006 study that re-examined the data, found that each execution results in five fewer homicides, and commuting a death sentence means five more homicides. “The results are robust, they don’t really go away,” he said. “I oppose the death penalty. But my results show that the death penalty (deters) — what am I going to do, hide them?”
Statistical studies like his are among a dozen papers since 2001 that capital punishment has deterrent effects. They all explore the same basic theory — if the cost of something (be it the purchase of an apple or the act of killing someone) becomes too high, people will change their behavior (forego apples or shy from murder).
I’m not quite sure that the science is quite that conclusive. Would the death penalty really have a deterrent effect on heat of passion murders? If people were that rational, the murder rate wouldn’t seem to be what it is. Still, the basic theory seems to hold. If someone knows that they can quite literally get away with murder, there’s a much greater chance that they will be more apt to kill. What remains to be seen is whether it’s really the death penalty that does it or the collateral effects of the death penalty. One would assume that a state with a death penalty would be less likely to be lenient in non-capital cases as well — although that’s a blind assumption on my part.
Still, this does raise a rather difficult moral question. If executing one (presumably guilty) party saves the lives of 5 innocents, is it morally permissible for the state to execute those found guilty of capital murder? What if the person isn’t guilty? If executing the innocent has the same deterrent effect how does that change the calculus?
I’ve always been on the fence when it comes to this issue. There are crucial moral and political objections to the idea that the state should have the power to execute someone — but at the same time, if there truly is a deterrent effect is it really moral to potentially trade the lives of many innocents for one person? Add to the mix the possibility of executing the innocent and things get more complicated.
Even if the evidence is conclusive that capital punishment deters murders, that doesn’t answer the deeper moral questions surrounding this issue. Even if the death penalty does work, society still has to come to grips with the moral implications of such a calculus — and that is an issue that remains one that should be up to the individual conscience of voters rather than the unelected courts.