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?
It isn't the desire to abide by the law that makes everyone behave as society requires, but the fear of punishment. Each one of us carries a gallows inside us.
I personally have always voted for the death penalty because I believe that people who go out prepared to take the lives of other people forfeit their own right to live. I believe that that death penalty should be used only very rarely, but I believe that no-one should go out certain that no matter how cruel, how vicious, how hideous their murder, they themselves will not suffer the death penalty.
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.
Criminals, people who commit crimes, usually society rejects these people. They are also part of our society. Give them some form of punishment to say they were wrong, but show them they are part of society and can change. Show them compassion.
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?
Even if a civil society were to be dissolved by the consent of all its members (e.g., if a people inhabiting an island decided to separate and disperse throughout the world), the last murderer remaining in prison would first have to be executed, so that each has done to him what his deeds deserve and blood guilt does not cling to the people for not having insisted upon this punishment; for otherwise the people can be regarded as collaborators in his public violation of justice.
If you want to be a grocer, or a general, or a politician, or a judge, you will invariably become it; that is your punishment. If you never know what you want to be, if you live what some might call the dynamic life but what I will call the artistic life, if each day you are unsure of who you are and what you know you will never become anything, and that is your reward.
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.
Speaking generally, punishment hardens and numbs, it produces concentration, it sharpens the consciousness of alienation, it strengthens the power of resistance.