I don't reconcile them. I'm religious and believe the death penalty is wrong for any reason under any circumstances. Because I'm religious though I know people who do not have this view and believe the death penalty is fine. They tend to use the deterrent to crime and protection of society arguments as well as mentioning certain old testament Levitical laws which make the distinction between justified and unjustified killing. Killing someone in self-defense, a soldier killing during war or the state killing as punishment for certain crimes versus an individual killing another.