We lost a lot of our basic ability to define and understand some people when we abandoned "evil" as a concept. There is evil in the world. There are evil people who do evil deeds.
Cohey (sp?) who kidnapped Jessica Lunsford may be an example.
The question really is this: Does having and using a death penalty make the world a better place by eliminating evil, one perp at a time.
A Death penalty is meant to be a deterrant to committing evil. For every person that faces it, the theory is that thousands more will avoid the actions that led to a criminal earning the sentence.
Without the campanionship of morality, absolutes of good and evil, and a reason to desire life over death in a culture? It becomes no more of a threat than a parking ticket.
I support the Death penalty, but it's viability as a deterrant against evil decreases as the culture fails.