It is necessary that people are protected from the thugs of our society - such as Lord Denning, famous for saying:
"It is better that some innocent men remain in jail than the integrity of the English judicial system be impugned".
Come up with an infallible system for exposing criminals, then you might eventually reach a fair way of punishing them.
We should be thankful that capital punishment is now as much a thing of the past as the thumbscrew and the rack, and as likely to be re-introduced.
Jim Carroll