just war

   The tradition dating back to classical and medieval literature that in certain cases it is ethically right to wage war and would be ethically wrong not so to do. Initially a Christian tradition dating back to the conversion of Emperor Constantine to Christianity in the fourth century, the idea has support from the world’s other great ethical traditions. Augustine, bishop of Hippo in North Africa, initiated just-war thinking in the Christian West when he wrote that he did not approve of killing in order to defend his own life but that it was right for public functionaries responsible for ‘the defence of others’ to do so when necessary.

   The presumption among supporters of just-war theory is that war is an evil but sometimes it is necessary to fight, although fighting should be limited to the minimum necessary to achieve the desired goal. There is no definitive set of criteria for a just war but it is usual to distinguish between war decision criteria (whether war is justified, jus ad bellum) and war conduct criteria (how war should be fought, jus in bello), both of which must apply for hostilities to be deemed to be just. War decision criteria include: legitimate authority; a just cause; right intention; a reasonable prospect of success; likelihood that the war will lead to a just peace; and last resort. War conduct criteria include proportionality and discrimination (not intentionally harming innocent citizens). International law follows the just war jus in bello tradition in the limits it places on certain modes of warfare via the Hague and Geneva conventions.