DEATH PENALTY DETERRENCE
Does the death penalty deter crime? Of course it does, at least by those who are executed. The tougher question is: does the threat of the death penalty deter the living from committing crimes? There is much disagreement and the proposition is neither provable nor disprovable. Even if the answer is "no" or "maybe", arguments exist for the death penalty -- sufficient arguments, in my view. My favorite is: "We shoot rabid dogs, don't we?" But if there is no deterrence (other than the simple case ) arguing deterrence lacks intellectual, not to mention persuasive, merit. Worse, death penalty proponents play into the opposition's hands by arguing deterrence as the prime reason to have a death penalty, given the problematic nature of proving deterrence. Why lead with an argument whose premise is disputable? I suspect it's because arguing punishment, or more to the point, vengeance, discomfits proponents who are trying to appear sensitive (or convince themselves that they are in fact too sensitive to be motivated by such base desires). News flash: reliable punishment for wrongdoing is not only OK but essential to a civilization's survival, and vengeance for heinous acts is often appropriate.
Don't get caught in the deterrence trap.