The History of War

The withdrawal of the last American troops from Afghanistan in August 2021 brought an end to 20 years of war, raising familiar questions about the utility of war itself. How do we assess the impact of a conflict that consumed tens of thousands of lives and hundreds of billions of dollars, only to end with the resurgence of the Taliban in greater strength than ever? According to the religious theory of the Just War, the cost is not so much the point as the moral intent behind it. International relations theories offer more pragmatic but still deeply subjective views. Why do nations really go to war, and does it ever serve the greater good?

Applying Augustine and Aquinas

Saint Augustine of Hippo may be the most influential theologian in the evolution of Western Christianity. To Augustine can be attributed many of the distinguishing doctrines of the Roman Catholic Church and its Protestant offshoots. Martin Luther was a lifelong Augustinian, the distinctly Western flavor of Reformation theology (as opposed to the theologies of Orthodox and other Eastern Christians) continuing to belie Protestant claims to have transcended Catholicism. It was Augustine, for instance, who first theologized the doctrines of original sin, free will, predestination, limbo, concupiscence, and filioque, and the theory of the Just War.

Augustine’s life spanned the declining years of the Western Roman Empire. He compiled his teachings at a time when Christianity was first becoming institutionalized in Rome after centuries of persecution, even as Rome was coming under threat from Germanic invaders. Western Christianity therefore faced what was arguably its most potent existential threat up to that point. At a time when the Church remained largely decentralized, it fell to Augustine to formulate a theological justification for armed resistance, contravening the Gospels’ principle of “turn the other cheek.”

The Just War formula, as devised by Augustine, would posit that war was justifiable when its leaders (as opposed to its soldiers, who should serve their anointed authorities regardless) sincerely meant to pursue a greater Christian good. Protecting the lives and property of their own subjects against unwarranted attack, for instance, or chastising sinners and nonbelievers. Much of Augustine’s theology seems disturbingly self-righteous and authoritarian by today’s standards, but it remains the basis of modern moral theories of violence.

Saint Thomas Aquinas in the thirteenth century took Augustine a step further. His contribution was to systematize Augustine’s rather vague principles into a more concise formulation. Aquinas refined the Just War to three predicates:

(1) Right authority (“Authority to command the waging of war belongs to the ruler […] and to no private person.”)

(2) Just cause (“Those who are warred against must deserve it for ‘some guilt,’ and the war finds its just cause in ‘avenging wrongs’ or restoring misappropriated goods.”)

(3) Right intention (to “promote good or avert evil.”)

Aquinas imbibed an era that may have been more warlike than Augustine’s, and in which the Church had long since embraced wholeheartedly the principle of holy war.

Outmoded though some of their assumptions might be, it is difficult to argue with the spirit of these teachings. A modern democratic leader could hardly justify any military undertaking without appealing to the same basic concerns. This is not the same, unfortunately, as saying that war always or usually results foremost from ethical concerns, or that it ever has.

Applying International Relations Theory

There are many schools of thought in international relations theory. Perhaps the most influential branch is realism, which prides itself on observing the international system not as it should function but as it does function. Such thinkers as Machiavelli and Hobbes are considered precursors of realism. There are different schools within realism, but they all emphasize the role played by power relations and self-interest in human affairs.

John Mearsheimer, a leading neorealist scholar, posits that survival is the principal goal – not the only goal but the principal goal – of every state, “because, if you don’t survive, you can’t pursue any other goals!” According to this perspective, states go to war when they feel their own long-term existence or short-term wellbeing is threatened by the activities of another state. Peace and cooperation are better for everybody, but states, like human beings, are egoistic. We cannot help but value our own wellbeing at least slightly higher than that of others, most of the time.

Egoism is one of realism’s four key assumptions. The egoist factor affirms the priority of self-interest over morality. The other three assumptions are:

(1) State-centrism (“[S]tates […] increase their power and engage in power-balancing for the purpose of deterring potential aggressors.”)

(2) Anarchy (“Each state is responsible for its own survival and […] its own interests.”)

(3) Power politics (“Realists…claim there is no place for morality in international relations, […] or that morality, if employed at all, is merely used instrumentally to justify states’ conduct.”)

International conflict therefore results from states assuming they have the capacity to win a war and that it is in their best interests to go to war. The opposing theoretical school known as liberalism, which emphasizes state preferences over state power, disputes this point in particular, noting that, in such conflicts as the Korean War and the Vietnam War, there was enormous enthusiasm for war in the smaller states despite the overwhelming resources arrayed against them. These critiques miss the point that, as Mearsheimer says, the first concern of every actor is survival, and in these conflicts, survival was already very much on the line for these states – a key component in the outcomes of those wars.

It is as tempting to dismiss realism for its cynicism as it is to dismiss Augustine and Aquinas for their medieval religious egoism, but we can afford to dismiss neither if we want to understand the phenomenon of war and the processes by which it is justified and rationalized. What seems indisputable is that humans, like all living organisms, are self-interested, and that self-interest and survival are a mutually reinforcing combination.

Reconciling Augustine and Mearsheimer?

The ideals of Augustine and Aquinas are self-evidently incompatible with realism, particularly the “offensive realism” proposed by Mearsheimer, but there is one area in which they overlap. Augustine, we have noted, was motivated by real-world duress to formulate the first theory of the Just War in the context of a broader, theoretically pacifist, philosophy. Political realism likewise professes peace as the most desirable condition but recognizes that conflicting interests are a prime mover in human events. Morality and pragmatism are not always reconcilable, but represent mutually indispensable keystones of civilization.

We need not favor one side over the other. We can no more afford to dispense with rational self-interest than we can afford to dispense with cultural values, both of which can and do lead to conflict, arguably to all conflict. The caveat is that we must be careful not to slip into irrational self-interest or moral self-righteousness.

The war in Afghanistan, like those in Vietnam and Korea, is a demonstration of where these miscalculations lead. The United States, like the Russians before us and the British before them, learned this the hard way. The Afghanistan offensive, like the War on Terror generally, is not justified by Augustinian theology or realist theory. Afghanistan, a nation-state with a supremely defensible topography and a culture sustained over millennia by nothing but the will to survive, has more than earned its nickname as the Graveyard of Empires.

This is not to say that war is never justified, particularly against ‘terrorist’ organizations like the Taliban. The moral problem with America’s offensive against the Taliban was that it was not motivated by moral concerns but by self-interest. The strategic problem was that America’s interests were never really served by the war in Afghanistan, at least not the way it was conducted. Had American policy been more empathetic and less selfish (to be distinguished from self-interested), it could have much better served both American and Afghan interests. (Note that the Taliban’s interests are not to be conflated with Afghan interests.) American foreign policy since the Cold War has regularly met the first two of Aquinas’ criteria (right authority, just cause) but dropped the ball on the third (right intention).

It may be possible to morally justify a war against the Taliban (not to mention ISIL, Hezbollah, Hamas, et cetera). An organization that practices “public executions of convicted murderers and adulterers, and amputations for those found guilty of theft,” while suppressing many basic freedoms and closely restricting education and other rights for girls and women can be fairly accused of bearing ‘some guilt’ (even if none of these activities would have seemed unusual to Augustine or Aquinas). But even this does not mean we should go to war.

Morally, it is difficult at the best of times to keep our intentions righteous without becoming self-righteous. Strategically, even a morally justified war does not serve the greater good if it is poorly conducted and thereby exacerbates the original wrongdoing. Most wars probably violate both principles. American interventionism in the Middle East and elsewhere generally has. Before we can fix the world, we need to fix our moral intentions.