When the courts put an innocent man in jail, they can release him if they later discover that they made an error. However, when the state executes an innocent man, no one can bring him back from the dead.
I am no legal expert; but, from a layman’s point of view, I would say to prevent the killing of non-murderers we must make sure that we have absolute proof of the murderer’s guilt through a lengthy judicial process with many appeals. I recommend there at least be a waiting period of *ten years*, or higher, from the time of death sentence until the execution. In regard to the death penalty, a speedy trial — at the expense of justice — is what we do not need.
The principle here is: it is better to let one hundred murderers go free, rather than to execute a single innocent individual. This is because the killing of a murderer is the destruction of evil — from which we gain nothing; the killing of an innocent individual is the destruction of the good — an irreparable loss. Justice’s first purpose is not to punish evil; it is to reward the good. The punishment of evil is a corollary of the rewarding of the good.