Just war theory (
jus bellum iustum) is a
doctrine, also referred to as a
tradition, of military ethics studied by
theologians,
ethicists,
policy makers, and military leaders. The purpose of the doctrine is to ensure war is morally justifiable through a series of criteria, all of which must be met for a war to be considered just. The criteria are split into two groups: ‘the right to go to war’ (
jus ad bellum) and ‘right conduct in war’ (
jus in bello). The first concerns the morality of going to war and the second with moral conduct within war. Recently there have been calls for the inclusion of a third category of just war theory - jus post bellum - dealing with the morality of post-war settlement and reconstruction.