The second condition Aquinas explicitly lays out (and derives from Augustine) is that of just cause, “namely that those who are attacked, should be attacked because they deserve it on account of some fault.” This idea of entering into war with those who deserve to be punished hearkens back to Augustine’s conception of war as a tool used by God to further His ends in relationship to the nations, and even further back to the military feats of Joshua and David. Additionally, it assumes that the attackers are in the right. It is this recognition of the rightness of their situation that justifies them entering into battle. This just cause condition also rests upon the presupposition of a natural order—in which the harmony and peace that is disrupted by a wrong action must be set right again. The country prosecuting the war has the right to do so because it is restoring peace and harmony.
A consideration of the end or goal of war leads to the final condition set forth by Aquinas and Augustine. Aquinas and Augustine argue that a war is just only if it is carried out with right intentions (in conjunction with the previously mentioned conditions). These intentions are broadly the same for both theologians; the aim or purpose of the just war is to bring about peace, or to advance what is good and avoid what is evil.
Aquinas conceives of peace, good, and evil on a broad and public scale. He recognizes the importance of the protection and advancement of the common good, and places the responsibility to defend this in the hands of the ruler based on his conception of natural order. War is carried out for the sake of peace, particularly the peace of the state. Augustine, on the other hand, is also concerned with the well being of the individual soul. He draws a comparison between a father disciplining his son for his improvement and one state going to war with another in order to prevent it from continuing to do evil and therefore never attain the true peace found only in doing good. He goes on to explain that the true end of war should be the benefit of the souls of men, who if they are unwilling to listen to sound moral teaching, may be forcefully made to obey these precepts for the common good as well as for their own benefit. He writes, “And in mercy, also, if such a thing were possible, even wars might be waged by the good, in order that, by bringing under the yoke the unbridled lusts of men, those vices might be abolished which ought, under a just government, to be either extirpated or suppressed.”
Even with this is significant difference between Augustine and Aquinas’ views on proper intentions, the important point to see is that both are agreed that war can only be justly waged with right intentions. Further, they agree on what these intentions cannot be; they cannot be “love of violence, revengeful cruelty, fierce and implacable enmity, wild resistance, and the lust of power.” The difference in their views lies not in what the broad intentions must be (viz. seeking peace and order), but only in how far the state must extend its influence in bringing about peace. Aquinas limits himself to the common good, while Augustine extends his considerations to the vices of individual men.
Coming soon…brief history of Islamic political theory.
Other posts in the Jihad and Justice series: