Capital punishment kills immediately, whereas lifetime imprisonment does so slowly. Which executioner is more humane? The one who kills you in a few minutes, or the one who wrests your life from you in the course of many years?
The contagion of crime is like that of the plague. Criminals collected together corrupt each other. They are worse than ever when, at the termination of their punishment, they return to society.
But secondly you say 'society must exact vengeance, and society must punish'. Wrong on both counts. Vengeance comes from the individual and punishment from God.
A material resurrection seems strange and even absurd except for purposes of punishment, and all punishment which is to revenge rather than correct must be morally wrong, and when the World is at an end, what moral or warning purpose can eternal tortures answer?
Without cruelty there is no festival: thus the longest and most ancient part of human history teaches and in punishment there is so much that is festive!
Guide the people by law, subdue them by punishment; they may shun crime, but will be void of shame. Guide them by example, subdue them by courtesy; they will learn shame, and come to be good.
There are limits to the smiles and scowls of diplomacy. Armies and missiles are not stopped by stiff notes of condemnation. They are held in check by strength and purpose and the promise of swift punishment.