Keeping that (and Objectivist philosophy in general) in mind, my first question is:
Is capital punishment moral?
Yes. It is not necessarily appropriate, but it is moral.
I have other questions, that we should only answer after we establish the morality of capital punishment:
Should we use the death penalty?
If so, in which cases? (I think it’s safe to assume the two possibly relevant criteria are the nature of the crime and the evidence that proves guilt. So please try and keep answers in this frame, or if not, mention the additional criteria.)
Criminal jutice has several purposes. One of them is retribution, the idea that a criminal must pay for his crime. It is sensible to set up retribution in kind with the crime commited. Thus stealing an apple merits a lesser punishment than stealing a car. If we proceed in increments, then for murder the appropriate punishment is death.
No one has a right to commit murder. There is a right to kill, though, of sorts. It is rightful to kill in self-defense or in defense of a third party, this includes up to a point the right to kill enemy combatants in time of war.
s to when is capital punishment appropriate, I’d reserve it for all cases of first-degree murder (that is when a person consciouslya nd deliberately chooses to kill another person and takes the willful action to do so), and some lesser crimes when there is an intent to destroy someone’s life.
The last is more complex. Let’s say aphotographer is so jealous of a colelague he pokes his eyes out. The intent is clearly to destroy or ruin the victim’s life. The problem is that there may be no rigorous standard by which to judge such things, and that determining intent cannot always be achieved (inferences don’t count).
I would accept, though not demand, the death penalty for some repeat offenders when the crimes are henious or brutal. Rapists, for example, child abusers, assault int he first degree and so on.
Now, one objection to the death penalty is the degree of certainty required for a positive sentence. That is, you’d best be damned sure you’re killing a guilty man. There have been many well-documented cases of innocent people punished, some even with death. Morally it is preferable to, as the saying goes, let a dozen guilty men go free than to convict one innocent man.
To begin with the prosecution should state it seeks the death penalty from the outset (I think this is already done in some US jurisdictions). Next in order to win a death sentence, the prosecution should be held to a standard that goes beyond a reasonable doubt. What that standrad is, I’m not yet sure. I won’t say “beyond any doubt,” because doubt can always be found (especially unreasonable doubt). But it would include such things as a reliance on phisical evidence and credible testimony.
I’d also proppose a lot of latitude in appeals, a long time between sentence and execution (say 3 to 5 years at least) in order to give the convicted a chance to appeal, and adequate legal representation when the defendant resorts to a court-appointed lawyer (and only then; if he hires an incompetent lawyer, that’s his affair).