Classicly

It is a disgrace to our civilization that men can be put to death by painful methods, which our laws have discarded as never suitable, and without the proofs of guilt which our laws call for in any case whatsoever. It would be a disgrace to us if amongst us men should burn a rattlesnake or a mad dog. The badness of the victim is not an element in the case at all. Torture and burning are forbidden, not because the victim is not bad enough, but because we are too good. It is on account of what we owe to ourselves that these methods are shameful to us, if we descend to them. It is evident, however, that public opinion is not educated up to this level.