IMHO, capital punishment is life affirming; it places the ultimate cost on the destruction of an innocent life. Actually, I think capital punishment should be on the table for any crime in which the victim would have been justified in using deadly force. In those circumstances, it is the criminal himself, and not society, or the law that has forfeited any claim on the sanctity of life.
Capital punishment should be used in cases of child rape but the SCOTUS shot it down. Oddly enough, even BO was for it.
Supreme Court Rejects Death Penalty for Child Rape
http://www.nytimes.com/2008/06/26/washington/26scotuscnd.html
Senator Barack Obama, the presumptive Democratic nominee, said, “I think that the rape of a small child, 6 or 8 years old, is a heinous crime, and if a state makes a decision under narrow, limited, well-defined circumstances, that the death penalty is at least potentially applicable, that does not violate our Constitution.” He added that the Supreme Court should have set conditions for imposing the death penalty for the crime, “but it basically had a blanket prohibition, and I disagree with the decision.”