21) Augustine also includes under the subject of necessity the just treatment of prisoners and conquered peoples, making it clear that mercy should be shown to the vanquished, particularly if they are no longer a threat to peace.(22) Besides right intention, St. Augustine also held that it was necessary for a war to be waged under lawful authority.(23) The purpose of the war-making powers of the state is to ensure peace, which in turn helps to foster the common-good of those in society.(24) Augustine recognised that it was necessary for the authority and decision to undertake war to be made by a recognised leader.(25) In addition, the soldiers who serve under the leader must serve the peace and common-good of society.(26) Warfare which is declared by unlawful authority therefore fails to meet this criteria, as does warfare which is not directed toward peace and the common good. The second major Christian thinker to deal with the issue of war is St. Thomas Aquinas (1225-1274).(27) Aquinas based himself upon St. Augustine's view of war, elaborating on the teachings of the bishop of Hippo.(28) In explicating his theory regarding the justness of a war, Aquinas focused on defining the right to make war and the importance of the intent which stands behind the decision to go to war.(29) In his attempt to formulate a simple rule which would give guidance on these issues, Aquinas argued that a war is justified when three basic, necessary conditions were met: 1. the war was prosecuted by a lawful authority with the power to wage war;(30) 2. The war was undertaken with just cause;(31) and 3. the war was undertaken with the right intention, that is, "to achieve some good or to avoid some evil."(32) Together with St. Augustine, Aquinas' views on the justification of war form the basic core of just war theory, and it is from their concepts that the theory of just war is adapted and expanded by later thinkers. 2. Se...
