Going off on last class, from the third image and imbalances of state, how a shift in balance of power leads to conflict. War is always judged twice, first with reference to the reasons states have for fighting, secondly with reference to the means they adopt (walzer) Jus ad bellum; jus in bello; jus post bellum y. In the context of the crusades, etc, the just war theory got developed. It s an old tradition that began in the deliberation of the catholic church. Jus ad bellum is what translates as justice in the decision to launch hostilities . Finally, jus post bellum is the justice post-war. This theory plays an important rold of justice in initiating a war, and how its prosecuted. The requirements of jus ad bellum are y. This is the reasoning for it, only as a self-defense act, and if it s not, it s considered the worst crime under un charter y last resort.