The Military Response to ISIS: a historical perspective

In the light of Parliament’s decision to approve military action in Syria, Rory Cox looks back to the classical and medieval world to ask: ‘What makes a just war?’

Rory Cox | Published 07 December 2015

Thomas Hobbes' book on the Peloponnesian War
Thomas Hobbes' book on the Peloponnesian War
Thucydides, the ancient Greek historian of the Peloponnesian War (431-404 BC), described how, at one point in the generation-long conflict, Athens was divided about how to deal with the rebellious city of Mytilene. Many Athenians supported a harsh military response, while others, led by Diodotus, urged restraint: 

Haste and anger are … the two greatest obstacles to wise counsel … the question is not so much whether they are guilty as whether we are making the right decision for ourselves … For those who make wise decisions are more formidable to their enemies than those who rush madly into strong action. 

The fundamental point made by Diodotus is that violence, whatever its justification, is often an obstacle to long-term stability. As today’s political leaders weigh the case for war against Islamic State, they must also ask themselves what they seek: vengeance, justice, stability, or peace?

An understandable desire for vengeance and justice impels the case for an enhanced military response to ISIS. However, when considered in an historical context, the strategic wisdom and even the ‘justice’ of a military response are far from obvious. Airstrikes are extremely unlikely to lead to stability in the region or security at home and the claim to be acting in self-defence may be weaker than it appears at first sight.

The recent attacks on civilians in Paris were abhorrent and cowardly. Since November 13th, France has stepped-up airstrikes against ISIS, declared a three-month-long state of emergency at home and was pivotal in drafting UN Resolution 2249, which exhorts other nations to take ‘all necessary measures’ to combat ISIS, claiming that the group represents a ‘global and unprecedented threat to international peace and security’. As a direct result, David Cameron has persuaded Parliament to expand UK military operations against ISIS targets into Syria, which he claims is politically, legally, and ethically justifiable.

The justification of such a military response may appear straightforward. As outlined in Article 51 of the UN Charter – cited by the Prime Minister to defend the legality of British airstrikes – France and Britain possess the rights of self-defence and collective self-defence of allies. A violent act of terrorism, perpetrated on French soil against unarmed civilians, constitutes a clear casus belli, necessitating a military response to punish a gross injury and limit future threats.

This kind of reasoning is broadly consistent with the just war tradition that has dominated Western ethical and legal thought for at least 2,500 years. Philosophers, theologians and jurists have stressed that wars should only be waged if certain conditions are present. There must be a just cause and a legitimate public authority to declare war. Armed conflict must always be a last resort, motivated by a desire for justice and peace rather than vengeance or profit. Presently, attacks like those in Paris are viewed by Western countries as offensive acts of aggression, unprovoked and unjust. Consequently, military responses are justified as acts of self-defence.

Based on a short-term view of events, this reasoning is persuasive. However, from a broader chronological perspective, the ethics, as well as the wisdom, of military responses to terrorism are far less clear-cut. Only when considered in a historical context – say a decade or more – can we begin to comprehend how those gunmen in Paris could be convinced that they were acting in self-defence and in the cause of justice. We might look back to the events surrounding the invasion of Iraq in 2003 as a starting point.

Islamic extremism feeds off the conviction held by many in the Middle East and elsewhere that the West bears a burden of responsibility for the region’s ills. This has been particularly apparent in the aftermath of the Second Gulf War. While the US-led operations against Saddam Hussein’s regime were militarily successful, the lack of a coherent post bellum strategy for political and economic reconstruction proved catastrophic. Needless to say, extremist groups distort and manipulate the reality of this history, but there is no escaping the fact that Western governments have played their part in pursuing a range of ill-conceived policies that have done little to enhance the stability of the region. Direct and indirect military intervention has proven particularly destabilising and has been a major factor in creating the conditions in which ISIS has flourished. This realisation forces us to ponder whether a military response to the Paris attacks can so confidently be justified as self-defence. Seen in this light, airstrikes in Syria are not a self-defensive reaction to an unprovoked injury, but rather another escalation of a long-running conflict – a conflict in which military force was initiated by Western governments.

The blame for killing hundreds of innocent people lies squarely on the shoulders of the individuals who commit and organise such attacks. I deplore ISIS and their brutality. I grieve for the lives they have destroyed; I mourn for the shattered ruins of Palmyra. Nevertheless, while many people fighting for ISIS are undoubtedly ignorant and cruel, some will be intelligent and convinced of the justice of their cause. This is the heart of the matter. Justice is a matter of perspective. It was for this reason that, from the late Middle Ages onwards, the Western just war tradition increasingly recognised the absolute right of sovereign states to identify and defend their own interests. This process really began with the Italian jurist Raphaël Fulgosius at the turn of the 15th century, but it gained significant momentum with the writings on war produced by the theologians and canon lawyers of the School of Salamanca during the 16th century. The legal right of independent states to wage war was most fully expressed by the Dutch jurist Hugo Grotius in his highly influential treatise De Jure Belli et Pacis (On the Law of War and Peace, 1625). This voluminous work is now widely regarded as the foundational text of modern international law. The basic realisation was that in wars between independent political communities, with each side claiming just cause, self-defence and sufficient authority, it was almost impossible to identify on which side (if any) justice truly resided. Who cast the first stone? Who was the aggressor and who the victim? Instead, Grotius argued that a common law existed among nations that should govern war and peace: the ius gentium, or ‘law of nations’. A ‘just war’, therefore, was a public war waged by two legitimate authorities in accord with the rules of war (ius in bello) established by the law of nations. In the West’s conflict against Islamic extremism, both sides claim to be acting in the cause of ‘justice’ and ‘self-defence’ – essentially a matter of perspective – but Western governments go further in claiming that only they, as sovereign states, have the legal right to use force. Terrorists are categorised as “non-state actors”, and are consequently denied the legal rights of prisoners-of-war as stipulated by the Hague and Geneva Conventions.

Long-term conflicts are typically resolved by two means: outright military victory or political reconciliation. The first is historically rare and may be unattainable in the fight against Islamic extremism. The second is slow and frustrating and fails to meet neither our desire for revenge nor our expectations of justice. The strategic value of military intervention is doubtful. We know from experience in Afghanistan and Iraq that killing jihadists does not diminish the allure of jihad: quite the opposite. Airstrikes and the inevitable civilian deaths that follow will certainly further alienate and potentially radicalise those who were not hostile previously. The sterile term ‘collateral damage’ will be used to disguise these civilian casualties, but they will be no less tragic than the lives lost in Paris. There is no doubt that an enhanced military response in Syria will provide further fuel for ISIS propaganda and make a long-term diplomatic solution harder to achieve. At some point, one side must have the courage to end the cycle of violence. It is clear that this must ultimately come from Western governments; it will not come from ISIS.

To step outside of a long-term historical process is difficult. But attempting to view recent events within a broader historical context may provide a valuable strategic perspective and prevent myopic policy decisions. It is impossible to predict how long this particular conflict will endure. Unfortunately, with all parties currently inclined to act in ‘haste and anger’, it will probably be several decades yet. Haste, anger and strong action may satisfy our human desire for vengeance; they may even fulfil our concept of justice. But as Thucydides witnessed 2,500 years ago, such a course rarely fosters stability, let alone peace.

Rory Cox is Lecturer in Late Mediæval History and Associate Director of the Institute of Intellectual History at the University of St Andrews. @DrRoryCox 

Get Miscellanies, our free weekly long read, in your inbox every week

The world's finest history magazine 3 for £5