This article by the governor of Maryland contains a lot of the usual reasons to be against the death penalty, which are wrong for the usual reasons. The death penalty is not actually a deterrent, he says, and executing someone is a lot costlier than just keeping them in prison for life. But one of the main reasons those two things are true is that anti-capital punishment people such as the governor have so complicated and lengthened the appeals process that people can sit on death row for 20 years. (And, as it has been pointed out by many people, the execution does deter one specific person.)
But he raises one issue that is troubling even to those of us who still feel the death penatly must be an option for some people who commit certain crimes:
These examples prompt a deeper question. Notwithstanding the executions of the rightly convicted, can the death penalty ever be justified as public policy when it inherently necessitates the occasional taking of wrongly convicted, innocent life? In Maryland, since 1978, we have executed five people and set one convicted man free when his innocence was discovered.
The most convincing argument against the death penalty, then, is not one of the usual liberal ones but a libertarian one. How can a government we think is barely competent to build roads be trusted with the most serious life-and-death issue there is? But even here we have to be careful. The "DNA tests show innocent people have been on death row" argument contains an obvious counterpoint: The DNA testing that wasn't available before is now and can help us be more sure that only the guilty face the death penalty.
