MH - The Price That Must Be Paid

Rich Leonardi presents the results of a study by the Brookings Institution on the death penalty:

Recent evidence suggests that capital punishment may have a significant deterrent effect, preventing as many as 18 murders for each execution, say Cass Sunstein and Adrian Vermeule of the AEI-Brookings Joint Center for Regulatory Studies.

Now, this is interesting; as Rich suggests:

Capital punishment presents a life-life tradeoff where a refusal to impose capital punishment could result in a significant increase in the number of deaths of innocent people. In other words, unjustified killing is exactly what capital punishment prevents, say the authors.

What does this say to JPII’s viewpoint that the death penalty was no longer necessary to protect society? I raised this point a whlie back [Seamless Garment], and Rich’s post certainly triggered an interesting (and high-level) discussion in the comments box, one that indirectly brings up further interesting questions. Someone mentions that JPII had ruled out deterrence as a legitimate justification for capital punishment. Now, if I understand correctly, this is the same argument that many make in calling the Iraq War an unjust war – that deterrence is not an acceptable rationalization for war.

My question – and I don’t know the answer – is this: in our modern age, when nuclear weapons in the hands of rogue nations or terrorist organizations has radically changed the nature of warfare, do we need to reexamine the question of pre-emptive or deterrent warfare? I understand the argument against this, that deterrence by definition can mean anticipating a result and acting accordingly, with no guarantee that the anticipation can be proven to have been correct; but often we do make that determination when dealing with self-defense. A policeman shouts to a suspect to freeze. The suspect reaches toward his pocket as if to pull something out. The policeman may decide that the suspect is going for his gun, and shoots him. Now, the suspect may have had a gun, and he may have been trying to pull out his wallet to show his ID. The shooting is sure to be controversial, but oftentimes the cop is given the benefit of the doubt. He had to act based on the information at hand, with a limited time to decide.

Some will argue that war is more important; that more time must be taken, that more information must be gathered. On the other hand, the reaction time has decreased dramatically. More and more lives are at stake. Is deterrence a basis for just war, and if so, what is the level of information required to make a proper decision?