How then should we understand “aggression”? The UN General Assembly has defined “aggression” as follows: “Aggression is the use of armed force by a State against the sovereignty, territorial integrity or political independence of another State or in any other manner inconsistent with the Charter of the United Nations.” This is a definition that Michael Walzer makes his own, and we should turn to his discussion as he is the author who has probably given the most cogent account of how the concept of aggression may be made central to a just war theory that licences some wars of defence against aggression under the heading of the JAB. As explained earlier, Walzer uses “the domestic analogy” to argue that war comes into its own, morally speaking, when a state exercises its right of self-defence against an attacking power. This right it gains, in his view, from the way legitimate political power is rooted in communal life.