States which have the death penalty have higher rates of murder than those who abolished it. Also those who reinstituted it saw no drop in murder rates.
The money it costs to keep a criminal on death row (legal bills) is greater than keeping them incarcerated for life.
Interestingly the law on this comes from the Old testaments, eye for an eye law, the Jews had one punishment that warranted the death sentence and that was murder. This draconic legal system was it is purported the inspiration for Americas laws. By the way Israel no longer has a death sentence, meaning they are more progressive than perhaps those of a fundementalist leaning, if you get my drift.
How do you judge a man as being incorrigable, is there a standard evaluation test that predicts sixty years of the rest of someone's life, who are you to play God?
How can a man atone for his crimes if he's dead? How do we know that he may never give anything back to society, serve as an example of a repentant man, lead others not to make his mistakes, we don't he's dead, darn
Revenge does not bring contentment in the famillies in question, it does not bring back the lost familly member and it is in the long term of no real consolation.
Quite apart from the fact that it's old fashoined and somewhat barbaric, The US I think will follow Europes lead in the end and fewer and fewer states will use it. I've yet to see anyone convince me that it does anything except waste money end life and increase murder rates.