found guilty beyond a reasonable doubt by a jury of their piers
See, that's the problem. How many news reports have we seen already just this year about people who were convicted of murder, (beyond a reasonable doubt and by a jury of their peers, obviously) but 20 years later additional evidence proved beyond beyond ANY doubt that they could not possibly have done the crime, and that person is immediately set free. Hell, I recall a story about someone who was on death row for decades who was just set free when he finally got someone to believe him and arrange for DNA testing.
Our justice system is in no way perfect. Innocent people ARE convicted of crimes they never comitted. There are many reasons why, from biased juries to incompetent defense attournies, etc. etc. I am with Vonk on this: if you imprison someone for life, and later evidence proves he was falsely convicted, you can still release him. If you've executed them, they're dead, and there's nothing you can do.
The possibility of the government killing an innocent person is just too horrible to contemplate. Imagine if that was YOU: you've done nothing whatsoever wrong, were not associated with a crime in any way, yet because of some situation beyond your control, you've just been convicted of a murder, and been sentenced to die. Imagine your fear and frustration as your execution day approaches (and very very rapidly if people like you had your way.) Saying it's unlikely is no defense, it happening ONCE is too many times, period.
Until we have a perfect system of determining who is and is not guilty of a crime, we cannot have the death penalty because of the potential for the state murdering innocent people. Given that we're human, and thus imperfect, I doubt sinceerely we'll EVER have a perfect system for determining guilt and innocence, and as a result, we should not have the death penalty.
In no way does that opinion change my belief that the person that did this is a monster (though still human, for all of that, and thus still possessed of those "inalienable rights" Jefferson spoke of), and makes me despair of humanity, that it would be capable of producing someone who could do those things. I meant it when i said maybe it's better if Humanity goes away if that's something we're capable of as a species. But death for death, torture for torture... these things we abandoned centuries ago, and for good reasons. Satisfying they may be to the primitive instincts, but that doesn't make them something we should follow. Obeying non-civilized instincts is what causes these problems in the first place, it does nothing to fix them.
-Arlos