I've been reading this thread for a while and have (so far) resisted the urge to weigh in. Partially because I wasn't sure that I could add anything to the discussion and partially because I wasn't really sure where I would draw the line beyond the obvious case of self-defense. Have had some time to think it over, though, I think I may have an answer. "When is it okay to kill someone?" -- Whenever doing so prevents injustice. I base this quick statement on a study of the doctrine of the "Just War:" Just Cause - Killing, as with a war, must be undertaken only to protect innocents from imminent danger. Competent Authority - Lawful instructions from proper authorities must be followed. In the set of questions above, the order to kill a terrorist is lawful, the order to take out his entire family (unless they are also terrorists) is not. Right Intention - Killing must be undertaken only for a just cause (protecting innocents from harm, see above.) Personal gain, either material or emotional (i.e. revenge) is not. Probability of Success - My act of killing another must have a reasonable chance of preventing the innocent party from coming to harm, or for stopping the harm that has been done to them. Last Resort - There must be no other viable options available, or no time to consider other options. Proportionality - The harm that I am seeking to prevent must be sufficiently grave to justify killing. (IMHO, loss of life, serious trauma, and harms of that ilk qualify.) Two exchanges from entertainment come to mind as well. The first is dialogue from FO3, when the Lone Wanderer is trying to convince Nathan that unquestioning support of the government is wrong, one of the dialogue options is "Well, why else would they have given us guns and told us, "If we're messing up, feel free to take us out."" The second is from the TV series Firefly: Zoe: "Shepherd, don't the Good Book have some pretty specific things to say about killing?" Book: "Why yes." (He cocks a shotgun.) "It is however, hazier on the subject of kneecaps." My final thought is a quote from Machiavelli, "Never do an enemy a small injury." :devil: