We don't know if capital punishment is a deterrent, but we know that men we execute will not murder again.
Mario PuzoThe other Dons in the room applauded and rose to shake hands with everybody in sight and to congratulate Don Corleone and Don Tattaglia on their new friendship. It was not perhaps the warmest friendship in the world, they would not send each other Christmas gift greetings, but they would not murder each other. That was friendship enough in this world, all that was needed.
Mario Puzo