The course of human history has demonstrated the great cost to lives and property that inevitably comes with war. As war has evolved over time, so too have diverse perspectives on thinking about it. At one extreme sits realism, asserting that in the pursuit of advantage, violence is human nature. Karl Von Clausewitz suggested that war had neither intrinsic limits nor could be externally limited. General William Sherman later described war as cruelty incapable of refinement. For realist thinkers Carneades and Machiavelli, maintaining the sovereign was the paramount consideration in resorting to war. The inhumanity that results is an unavoidable side effect or even necessary activity given the pressures faced in conflict. Representing the other extreme is pacifism, contending even one who is attacked should not fight back, much less launch an offensive war.
Both extremes elucidate very simplistic viewpoints. Despite the evils of war, it would be wrong to deny its necessity at times. While war has served those who seek conquest, so too has it served to defend against them, marked in recent history by the defeat of Nazism in Europe. Just as war may serve as an implement for those with evil intentions, so too can it serve those who, as Thomas Aquinas posited, wage it out of a desire for peace.
Balancing these two extremes, just war theory contributes to a tradition of thought and principles regarding the recourse to and conduct of war. Some of these principles are now reflected in humanitarian law, the laws of war. However, as with war itself, just war theory and humanitarian law are capable of serving both those with good and bad intentions. For while they have spurred the creation of limits that seek to restrict the harm of war, they have also been invoked by those seeking to justify what is arguably unjust.
Just War and Humanitarian Law
Existing between pacifism and realism, just war theory shares the aversion to violence of the former while accepting that circumstances may arise where war is ethically justified. The tradition has evolved over time with contributions from thinkers seeking to answer two basic questions; when may war be used and how must it be waged? The principles that have developed to answer these questions are categorised as the jus ad bellum and jus in bello respectively.
The jus ad bellum deems war permissible only where it is waged by a competent authority for a just cause (traditionally self-defence), who does so with the right intention. To go to war must be the last preferred option (“last resort”). The war must have a reasonable prospect of succeeding, with costs not disproportionate to what can be gained from it. The jus in bello attempts to limit the carnage in conflict by requiring parties to recognise the immunity of non-combatants, and ensure that harm is not disproportionate to the good that may come from conduct within the conflict. Some of these principles are reflected in humanitarian law. The United Nations Charter of 1949 and preceding instruments mirror the ad bellum principle of just cause, limiting recourse to war to self-defence. The Geneva Conventions codified distinction between and standards for treatment of combatants and non-combatants.
Those critical of just war theory and humanitarian law point to their perceived failures to deal with the costly wars of the twentieth century. Humanitarian law often developed as a reactionary tool, with major instruments forming in response to the ravages of the world wars. For periods in history, the just war tradition has been forgotten or dismissed in favour of the belief that states should be able to wage war based on their subjective interests – the doctrine of raison d’état. To be sure, there are examples that point against the efficacy of just war theory and humanitarian law. US strategy in Korea deliberately targeted locations to harm civilian morale while campaigns in Vietnam resulted in the destruction of farmland and forests, neither of which showed regard for the principles of proportionality and discrimination in war. However, to deny that just war theory and humanitarian law can serve a useful purpose would be akin to dismissing domestic law as invalid if some do not obey it. One cannot ignore the progress made on issues such as land mines, a weapon deplored for lacking discrimination, where humanitarian law has done much to limit their use and spur their clean up. Nor can we ignore the broad legitimacy with which humanitarian law and just war principles are held in the international arena.
States, though, are able to interpret them in ways that are repugnant to their spirit and invoke them to justify what is arguably unjust. The actions and strategic pronouncements of the US regarding the war on terror have on occasion mirrored raison d’état , dismissing their applicability. Yet the United States has invoked both of them to give legitimacy to their strategic endeavours too. Rather than regulating global conflict, they can become weapons for global conflict.
The war on terror and Afghanistan
Prior to the attacks of September 11, responses to terrorism focused on law enforcement and criminalising specific acts. Following the attacks, US strategy shifted, declaring a “war” on terrorism and vowing to defeat all groups with global reach. Reconciling the war on terror and US conduct toward terror suspects with just war theory and humanitarian law is problematic.
Terrorism is a broad concept, for which an internationally recognised definition has proven elusive. The US Department of Defence describes terrorists as those who use “force or violence against persons or property to intimidate or coerce.” Bellamy asserts that a war against such a vague foe cannot be “just” given the inability to assign a just cause to all terror groups alike. In light of the number of groups to which the definition above could apply, I would agree. Vitoria spoke of the sole just cause for war being defence when harm has been suffered, a view reflected in the UN Charter. While this may apply to Al-Qaeda for sponsoring 9/11 and the Taliban via state responsibility in international law, one cannot attribute this just cause to terrorism, with its diverse actors and aims as a whole.
With such a vague target, the ad bellum and in bello principles of proportionality become more difficult to calculate. Rodin ponders whether the millions who died and lasting effects on Europe were worth the price in defeating Nazism. Walzer concluded the effort, including bombing German cities was, given the “immeasurable evil” of Nazi victory. Calculating proportionality is difficult, for the length and stakes of war cannot be predicted with certainty. Murray spoke of the need to make a “moral calculus” based on factors including who is to be fought and what is at stake. Though Walzer described the Nazi triumph as immeasurable, the allies knew of the size and capacity of the axis powers and of the populations at risk of being subject to their rule.
The same cannot be said for terrorism. Osama Bin Laden (citing the Quranic equivalent of just war theory) characterised the group’s actions as defensive against the perceived western invasion of the “umma,” and more specifically the “occupation” of the holy lands. At other times though, Al-Qaeda spoke of killing every American. The gravity of the threat defines the level of force we may use and the cost we are willing to pay, yet against an abstract foe whose intent, capacity and numbers are fluid and ill-defined, determining the potential costs against the potential benefits of going to war is difficult. Even a single target like Al-Qaeda is more akin to a franchise with loosely connected outlets rather than a single body. Bin Laden’s views have been rejected even by fellow radical Islamist figures such as Hamas founder (and according to the definition above, terrorist leader) Ahmed Yasin. While the US has attempted to draw parallels between the threat of Nazism and terrorism, the latter has fragmentation and subtlety the other did not.
Characterising the war on terror as war brings with it responsibilities and freedoms regarding the in bello principle of discrimination and treatment of persons under humanitarian law. The indeterminate boundaries of the conflict have given the United States broad latitude, including carrying out the targeted killing of terror suspects that would otherwise be more clearly prohibited as extra judicial punishment under international law. As the US has capitalised on this wartime freedom, it has obfuscated its responsibilities for the treatment of those captured. Afghan suspects from 2002 onwards were denied any of the recognised classifications under relevant conventions and labelled “unlawful combatants” instead.
Expanding the war: Iraq
The 2003 invasion of Iraq demonstrated the strained invocation of just war principles and humanitarian law for an unjust cause. Formal justification for intervention rested on reactivating UN resolutions from the 1990s, a move of doubtful legal soundness given the passage of time and vastly different circumstances to those the resolutions specified. This also casts doubt on whether ad bellum authority existed, as neither the US itself possessed it justly nor is it likely it was legally derived from an international body. The US additionally invoked the language of just war theory to support its cause, using the controversial notion of preventative versus pre-emptive war. The US justification centred on Iraq’s weapons of mass destruction and perceived willingness to share them with terrorists. That Iraq had neither attacked the US nor was there any indication an attack was imminent meant US action was preventative, described by Grotius as an unjust cause. US doctrine framed just cause as preventing a “serious” threat rather than pre-empting the “imminent” threat more readily accepted in just war theory.
The perils of using just war theory and laws of war against terrorism
Considering the problematic nature of fighting terrorism with war, is this approach suitable, or even desirable? With just war and humanitarian law come responsibilities that attach to parties to a conflict and legitimacy for the actions engaged in. It is neither possible to attach those responsibilities to a foe as vague as terrorism nor is it desirable to give terrorists the legitimacy of engaging in formal armed conflict. Terrorist activities are criminal, as recognised by international legal instruments, and should be treated accordingly.
It must also be recognised that entering into a conflict characterised as war may serve the purposes of terrorists. Bin Laden framed Al-Qaeda’s campaign as defensive jihad against western invasion of the holy lands. Though Bin Laden’s interpretation is widely held to be faulty, utilising large-scale armed force risks lending credence to his claims, at least to those who may choose to support him. Indeed using force can push different people and groups together for a common interest, unifying terrorist elements. One concludes from this that a return to the emphasis on law enforcement would be desirable.
“Those who have been attacked are permitted to take up arms because they have been wronged.” Though similar, these are not the words of just war thinkers like Augustine, Aquinas, Vitroria or Suarez, but a Quranic verse cited by Osama Bin Laden justifying attacks on America. It is poignant for it illustrates the inherent weakness of law and theory… the reliance on those who interpret and use it. The Islamic equivalent of just war theory was invoked by Al-Qaeda to justify its deeds, though their interpretation of it was judged as flawed by Islamic thinkers. Just war theory and humanitarian law cannot be dismissed as intellectual folly serving no practical purpose. They have done and continue to have the great potential to promote good. They however are merely tools that require a hand to wield them. If a state interprets them vulgarly or chooses to ignore them, the culpability belongs to the state that does so. Vitoria spoke of circumstances where both sides believe their cause just, stating that decision makers should exercise diligence and probity while seeking opportunities for arbitration and mediation. The United States though has not demonstrated this, instead turning to just war theory and humanitarian law as a weapon of war.
 Christian Enemark and Christopher Michaelsen, “Just War Doctrine and the Invasion of Iraq,” Australian Journal of Politics and History 51:4 (2005) 545. 545.
 Gregory M Reichberg, “Just Ad Bellum”, in War: Essays in Political Philosophy. Ed. Larry May (New York: Cambridge University Press, 2008) 11. 14.
 Michael Walzer, Just and Unjust Wars (New York: Basic Books, 1977) 23.
 Michael W Lewis, The War on Terror and the Laws of War (New York: Oxford University Press, 2009) 4.
 Larry May, Aggression and Crimes against Peace (New York: Cambridge University Press, 2008) 26.
 Anicee Van Engeland, Civilian of Combatant? A Challenge for the 21st Century (New York: Oxford University Press, 2011) 7.
 Raymond Kuo, “Occupation and Just War”, International Relations 22:3 (2008) 299. 300.
 Larry May and Emily Crookston, “Introduction” in War: Essays in Political Philosophy, ed. Larry May (New York: Cambridge University Press, 2008) 1. 2.
 David Fisher, Morality and War (New York: Oxford University Press, 2011) 66.
 Ibid., 67.
 Reichberg, War: Essays in Political Philosophy, 11.
 Gabor Rona, “Interesting Times for International Humanitarian Law: Challenges from the War on Terror”, Political Violence 17:1 (2005) 157. 158.
 Reichberg, War: Essays in Political Philosophy, 11.
 Mathew Evangelista, Law, Ethics and the War on Terror (Cambridge: Polity Books, 2008) 35.
 Ibid., 13.
 Ibid., 69.
 Nigel White, “Terrorism, security and international law” in International Law, Security and Ethics, eds. Aidan Hehir, Natasha Kuhurt and Andrew Mumford (London: Routledge, 2011) 9. 15.
 Evangelista, Law, Ethics and the war on terror, 60.; Nicholas Wheeler, “Dying for ‘Enduring Freedom’ Accepting Responsibility for Civilian Casualties in the War against Terrorism”, International Relations 16:2 (2002) 205. 205.
 Uwe Steinhoff, On the Ethics of War and Terrorism (New York: Oxford University Press, 2007) 110.
 Alex Bellamy, “Is the war on terror just?” International Relations 19:3 (2007) 275. 291.
 Alia Brahimi, Jihad and Just War in the War on Terror (New York: Oxford University Press, 2010) 24.
 David Fisher, Morality and War (New York: Oxford University Press, 2011) 74.
 Terrence Kelly, “The just conduct of war against Islamic terror and insurgencies”, in The Price of Peace, eds. Charles Reed and David Ryall (Cambridge: Cambridge University Press, 2007)
 Brahimi, Jihad and Just War in the War on Terror, 112.
 Ibid,. 99.
 Nicholas Wheeler, “Dying for “Enduring Freedom’ Accepting Responsibility for Civilian Casualties in the War against Terrorism, International Relations 16:2 (2002) 205. 215
 Elizabeth Bates, Terrorism and International Law: Accountability, Remedies and Reform (New York: Oxford University Press, 2011) 234.
 Evangilista, Law Ethics and the War on Terror, 62.
 Brahimi, Jihad and Just War in the War on Terror, 2.
 Christine Enemark and Christopher Michaelsen, “Just War Doctrine and the Invasion of Iraq”, Australian Journal of Politics and History 51:4 (2005) 545. 556.
 Ibid,. 550.
 Reichberg, War: Essays in Political Philosophy, 27.
 Marc Weller, Iraq and the use of force in International Law (New York: Oxford University Press, 2010)
 Rona, Terrorism and Political Violence, 159.
 Brahimi, Jihad and Just War in the War on Terror, 112.
 Robert Trager and Dessislava Zagorcheve, “Deterring Terrorism: It can be done”, International Security 30:3 (2005/06) 87. 121.
 Brahimi, Jihad and Just War in the War on Terror, 113.
 Ibid., 112.
 Reichberg, War: Essays in Political Philosophy, 21.