principles consist of the following three elements: 1) just cause; 2) competent authority; and 3) right intention.(66) Just cause is classically understood to refer to self-defence.(67) The use of military force is justified when it is used to repel an unjust aggressor and to retake that which the unjust aggressor has taken.(68) It is generally acknowledged that a nation may use force to protect a neighbouring state from attack from an outside hostile power.(69) Thus, defence of self, or defence of another, are legitimate reasons for a nation-state to resort to military force. The second element of jus ad bellum is that the war must be declared by competent authority.(70) As recognised by theorists like Cicero and Aquinas, for a war to be just, the decision to go to war must be lawfully made.(71) If an illegal or non-legal authority within an nation made the decision to go to war, such a decision would be unjust, for it would violate the basic principles of how a given society is governed.Finally, the war must be fought with right intention, meaning that the motives for the war must not be to inflict undue suffering on the enemy state; the defending nation must use only that amount of force which is necessary for it to achieve its just cause. The motives of those engaged in making the decision to go to war must not be tinged with vengeance or a desire for retribution. Rather, the decision to go to war must be essentially protective; the goal of war is to obtain a just and durable peace. Such a peace is unlikely if the war is waged out of hateful or vengeful motives, with a desire not solely for self-protection but the total destruction of the enemy. If in it's actions, the defending state's use of force exceeds what is necessary for the success of its just cause, the defending state's right intention is problematic. Seen this way, right intention serves to reinforce the requirement that the state which seeks to justly use force be ...
