The issue was that it is a matter of opinion if the death penalty is justice or murder. Not if the murderer is guilty or not.
Might says which one is correct. Some states (might) in the US say it is justice. Others governements (might) say that it is murder.
Might does make right.
This principle even applies to God. God is supposed to be the mightiest might. He makes the rules to wether what is right or not. Correct?
I have never read Nietsche btw. Not yet at least, from what I hear here it should be very interesting.