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Saint Augustine
Just War in the 21st Century - The Just War: Aquinas
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Just War in the 21st Century
Old Testament and War
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The Just War: Aquinas
Aquinas, like Augustine, was both a monk and a priest whose chief concern was for Christians to live in a way that would honour God on earth and lead to an eternity with God in heaven. He wrote extensively on how Christians should live and conduct themselves, addressing a vast array of issues—from Christian doctrine to individual moral conduct. In his writings, Aquinas brought together ideas from a huge number of sources, the most important Christian influence being Augustine and his most important philosophical influence being the Greek philosopher Aristotle: both of whom had written on the notion of the just war. It is worth noting that Aquinas was only able to incorporate Aristotle in his writings because the works of Aristotle had been preserved by scholars in the Middle-East and translated and brought to Europe during the Crusades. Having weighed up the key arguments of the theologians and philosophers who had come before him, Aquinas succinctly codified the conditions to be satisfied for a war to be considered just:

In order for a war to be just, three things are necessary. First, the authority of the sovereign by whose command the war is to be waged ... Secondly, a just cause is required, namely that those who are attacked, should be attacked because they deserve it on account of some fault ... Thirdly, it is necessary that the belligerents should have a rightful intention, so that they intend the advancement of good, or the avoidance of evil.29

The just war criteria that Aquinas set out – legitimate authority, just cause and right intention – are still at the heart of just war debate in the twenty-first century. However, there are some important differences to be taken into account. One of the differences between Aquinas’ time and the present is the relationship between political authorities and religious authorities. Aquinas wrote: ‘The secular power is subject to the spiritual, even as the body is subject to the soul’.30 It was important to him that war should be authorised and commanded by the sovereign (and thus being granted legitimacy) as well as being fought for a just cause. The sovereigns in Europe at that time were usually kings and princes who owed their religious allegiance to the Pope and the Catholic Church, and one of Aquinas’ reasons for trying to limit when wars could take place was to preserve the life of Christians who would therefore meet in battle. In contrast, there are few sovereigns in the modern world who could authorise war in the way that Aquinas described, and even fewer, if any, who would submit to religious authority.

With regard to Aquinas’ second criteria, just cause, in the current international system it is the responsibility of the United Nations (UN), and in particular the UN Security Council, to assess the causes of war and decide whether or not a particular war is legitimate or justified. In addition, individual states retain the sovereign right to self defence: ‘Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations’.31 When the Charter was written and signed by the victorious Allied Powers towards the end of World War II, limits were placed on that right to self-defence, with ultimate responsibility reverting to the Security Council: ‘The Security Council shall determine the existence of any threat to the peace, breach of the peace, or act of aggression and shall make recommendations, or decide what measures shall be taken … to maintain or restore international peace and security’.32 However, what could not have been foreseen as the UN Charter was drawn up was the subsequent rapid degeneration of relationships between the major powers as the Cold War emerged and permanent members of the Security Council33 began to use their veto powers to pursue vested political interests and to frustrate their political rivals. 

The UN has no enforcement powers or political sovereignty of its own through which it can enforce its will on intransigent nations or non-compliant actors, such as Iraq and Saddam Hussein.  When the UN Charter was written prior to the end of World War II, the Allied Powers had millions of men under arms in their various armies, navies and air forces and the text itself suggests that the Security Council would be able to enforce its will: ‘[The Security Council] … may take such action by air, sea, or land forces as may be necessary to maintain or restore international peace and security’.34 The political reality today is that the kind of action suggested here is all but impossible.  The ultimate testimony to the ineffectiveness of the UN and the Security Council to enforce peace and stability is found in the killing fields of Cambodia and Rwanda.  The third of Aquinas’ criteria for a just war, right intention, is very difficult to assess in the current state-centric international system. With so many competing interests it is difficult in most political settings to determine the intentions of the actors involved. The UN Security Council is limited in its ability to determine whether a particular war is just or not by the multiple layers of motivations that underpin the intentions of any state that sets out to engage militarily with another, even a defensive war.

Aquinas’ emphasis on right intention also has implications for soldiers who fight in battle. He took the biblical view that killing is wrong but, like Augustine, made an exception when it came to the soldier taking life in battle. Not only was killing in war acceptable for Aquinas, in the right circumstances it was positively the ethical thing to do. He wrote: ‘The common good of many is more Godlike than the good of an individual. Wherefore it is a virtuous action for a man to endanger even his own life, either for the spiritual or for the temporal common good of his country’.35 In other words, the soldier who endangers his own life, or who takes the life of another in battle, is carrying out a virtuous act: as long as the killing is for the common good, such as defence of the soldier’s country or those who cannot defend themselves. Even then, killing in battle is only justified if it is absolutely necessary. The soldier must be committed to upholding the common good by winning in battle. If the soldier’s intention is to kill as many people as possible, regardless of whether they are combatants engaged in the war or simply innocent bystanders, then that individual should be subject not only to God’s eternal punishment but to legal punishment on earth as well. Aquinas’ words on the use of force are relevant to both soldiers and civilians today:

Wherefore if a man, in self-defense, uses more than necessary violence, it will be unlawful: whereas if he repel force with moderation his defense will be lawful, because according to the jurists ... "it is lawful to repel force by force, provided one does not exceed the limits of a blameless defense."36

Soldiers on the field of battle today will be held legally accountable if they exceed the level of force authorised in their Rules of Engagement. Few will care about Aquinas’ notion of divine punishment, but in the case of a war crime being committed an individual could be prosecuted at the International Criminal Court. British soldiers have stood trial in British courts in recent years as a result of illegal actions in the face of the enemy in Iraq, such as the beating and even killing of prisoners. In the centuries since Aquinas wrote about just war, many other great thinkers have contributed to this tradition of thought. In recent centuries increasing emphasis has been placed on the conduct of soldiers in war and the two just war terms that guide such conduct, legally as well as ethically, are discrimination and proportionality. Discrimination, in the just war sense, stresses the importance of targeting only legitimate combatants and avoiding the killing of civilians or noncombatants. This idea is captured in the Geneva Conventions37, non-religious international humanitarian law to which the UK is a signatory, as well as individual combatants’ Rules of Engagement. A noncombatant is anyone not legitimately engaged in war. So, for example, once a soldier has been taken as a prisoner of war he or she is no longer a combatant. Similarly, a wounded enemy soldier who is disarmed and taken to hospital for treatment is a noncombatant. Yet it is clear that the kind of interventionist war being fought in Afghanistan, like the recent war in Iraq, is not between two armies whose soldiers are clearly identifiable as such.

The final section of this article will examine some of the particular ethical challenges surrounding war in the twenty-first century by exploring Tony Blair’s justification of the 2003 Iraq invasion, before going on to examine the ethical implications for combatants fighting against a highly motivated insurgent enemy. What becomes apparent is that while some of the philosophical underpinnings of just war remain in political and military discourse in the West (such as the pursuit of justice and the prevention of unnecessary death or suffering), the theological motivations that helped shape the tradition over many centuries are no longer applied and state policies are not dictated by a desire to enter the Christian’s heaven.

Last Updated on Thursday, 17 February 2011 14:46