I should preface this entry by stating that I have for some time been against the penalty on an absolute basis; I feel our laws should never allow for it. Nevertheless, I did read an interesting argument in favor of the death penalty at my favorite blog, The Economist's Democracy in America.
A post at DiA a few weeks ago brought up the death penalty, and much of the ensuing conversation focused on whether it acts as a deterrent or is just an ugly expression of vengeance. One poster made the interesting point that the death penalty is partially about revenge, but that it should be. The argument goes that laws should reflect society and human nature, and revenge is a part of human nature, for better or worse. Better to channel it through the less biased and more cool-headed legal system than to let individuals be the ones taking eyes for eyes, hands for hands and lives for lives.
I actually find that argument compelling, but not enough to change my mind. Laws should reflect human nature, true, but they can also be used to fix it. I know that sounds incredibly Orwellian, but consider that racial discrimination was made illegal far before it was made socially unacceptable, and the same is true of drunk driving and debtors' prisons. In the case of the death penalty, the government puts itself in an odd position by saying that certain people deserve being killed by the state, but don't deserve to be killed by individuals.
And although it's not related to the above, my second argument against the death penalty is as basic as it is boring: until we can ensure that the law is administered without biases or other human factors (professional ambitions, differences in competence between the prosecution and defense, etc.), the death penalty is going to inevitably result in some innocent executions. And that "until" will never happen.