Say a couple of people enter my house illegally, and they are openly carrying weapons. Let's say I even overhear them, and know that their intent is to do me, or my family, harm. Do you think I will leave myself any room for compunction over trying to stop these individuals by whatever means necessary? Is it wrong for me to defend myself to the point of killing a person who is attempting to kill me? In this scenario, they haven't even committed the crime of killing yet - even if they are swinging the knife at me, if I kill them first then they didn't get to kill. And yet, if I am allowed this self-defense, their death is justified.