Sounds like you and ckca were in the same class in "moral theology"! (BTW, sometime when you'e looking at what the Bible says, try Matthew 5:38-39.)
As the Church's teaching on contraception cannot "develop" in a way that would declare its intrinsic evil to be good, so the right of a state to execute criminals cannot "develop" so that its intrinsic good becomes evil. For Cardinal John Henry Newman, development of doctrine involves "preservation of type." Changes in the way a doctrine is expressed and applied cannot alter its essence.