What is the Just War theory?

FOR GCSE & A LEVELOVERVIEW: A just war is one that is fought for the correct reasons and on the basis of virtuous principles. In this case, a war is just because it is justified. In relation to Christian doctrine this theory was established by the theologians, Augustine and St Thomas Aquinas however it's roots can be traced back to the ancient Greek philosophers, Plato and Aristotle.The criteria for a just war is formed by two categories i.e. the right to go war, jus ad bellum, and the right conduct in war, jus in bello, however recent scholars have suggested the addition of a third category, justice after war, jus post bellum, in relation to fair peace treaties, the treatment of war criminals and the fair terms of reparations.For the purposes of Christian examination, the conditions laid out by Thomas Aquinas are as follows: 1) War must be waged by a legitmate and legal authorirty e.g. the state 2) War can only be waged for a greater good and purpose rather than self-interest and/or gain i.e self-defence as opposed to capturing territory. 3) The end goal and reason for war must have the aim of bringing peace.Two later conditions were then added by the Catholic church: 4) War must be the last resort after all other methods to restore peace have failed e.g. diplomacy 5) The war itself must be fought proportionally i.e. there must be no use of excessive force e.g. rape, nuclear weapons, and loss of innocent civilian lives.N.B. Have these conditions always been upheld in warfare? Can you name one case where they have and one case where they haven't? Consider: Other attitudes to war e.g. PacifismDo you think the conditions are realistic? What are their strengths/good points? What weaknesses/problems can you indentify? Consider: Human natureFinally, what is your opinion on warfare and the Just War theory? ​Consider: Is a war ever just? Why?