As an opponent to capital punishment, I was going to comment on Saddam Hussein and the possibility of his execution. However, Kevin Miller -- whose theological opinions I hold the deepest respect for -- already beat me to the punch. I agree that Saddam is the exception foreseen by the Catechism of the Catholic Church. While I do not believe that capital punishment should be used as retributive justice, no matter what atrocity is committed, there is always the danger that he could continue to inspire and lead the insurrection if kept alive. This would place other human life and the new Iraqi society at great risk. Therefore, unless Saddam openly and sincerely owns up to his past, denounces it, repents from it and agrees to spend the rest of his life doing penance for it (in which case he should be locked away in a maximum security American prison) this is one of those exceptions to the Church's prudential stand against capital punishment.
Pete, I am unable to see how Saddam is somehow the exception forseen by the Catechism. Perhaps you could expand on what you have written. The idea that we cannot execute Saddam for what he has done (retributive justice), but that we can execute him for what someone else might do (what would you call this, "preventative justice"?), strikes me as more than a little nutty and quite unjust.
As I read the Catechism (CCC 2266-2267), the punishment for a crime is supposed to be commensurate with the gravity of a crime. The death penalty is then held up as an exception to this general principle. Not because executing a person can never be commensurate with whatever crime they may have committed. But because it better fits the dignity of the "aggressor" as a human being that he or she not be killed. The exception to this being if "bloodless means" are insufficient to protect society from "the aggressor."
Suppose the fedayeen dramatically increase their terrorist attacks and issue communiques that they are doing this "for Saddam." Does that somehow make Saddam, who is in American military custody, who has no direct access to means of communication with anyone, who has no visitors except his military and CIA interrogators, who has no chance of escape whatsoever--does that somehow make Saddam "the aggressor"?
In such a situation, Saddam is no more an aggressor than a fetus is an aggressor in a woman's body. What you (and Kevin Miller) apparently suggest would sever all notion of personal responsibility from a just punishment.