Kutatás / Kereszténység és demokrácia

Theories of war: Christian and secular perspectives

We are often told that the world is more peaceful today than it ever was. The number of wars – especially that of “classic”, inter-state wars – is significantly lower than at any point in human history, and if ordinary people think otherwise (so the argument goes), they are simply misled by the tension between their pacifist expectations and the violent image of the world presented by today’s global and often sensationalistic media.

And there is some truth in that. When celebrated authors like Steven Pinker or Yuval Noah Harari write on the twilight of violence (see Pinker, 2011; Harari, 2016), they can indeed rely on statistics that show a perhaps not continuous, but – regarding the longer trends – definite decline in the number of wars and war victims, especially since World War II. If we also add that the decline of violence concerns not only wars and armed conflicts, but other instances of political and social violence – see the abolishment of the death penalty or the lower incidence of criminal or domestic violence in many countries around the world – the argument seems to become almost irresistible. That the public has a different impression only proves that our age is indeed more peaceful than all previous ones, rejecting physical violence and its justifications at a formerly unprecedented level.

All this may be true, but some caution is required, especially when speaking of longer historical periods. The fact that we have seen a decline in violence since the Second World War doesn’t necessarily prove that the same tendency will go on endlessly in the future. After all, the second half of the nineteenth century had already raised similar hopes about a more peaceful world before two world wars in the twentieth proved otherwise; and even the first decades following the Second World War were plagued with colonial wars, revolutions, and terrorist attacks before today’s alleged “most peaceful epoch of all times” would finally arrive. With some pessimism, one might also say that the longer a peaceful period is, the more violently it may end; but this is already the realm of prophecies, and not of scientific predictions.

What is not a prophecy, however, but a fact of our contemporary world is that – whether we accept the fundamental claims of the optimistic narrative or not – wars and other forms of violence are still with us. Old-fashioned inter-state wars may be less frequent, but countries like Armenia and Azerbaijan have been recently involved in such; civil wars have not disappeared from countries like Yemen, Syria, or Libya; while terrorism also regularly returns to the scene even in the West (see Paris or Vienna), not to mention more frequent instances in other parts of the world.

On the other hand, new forms of violence have also appeared. These are not necessarily “physical” in the traditional sense of the word but involve a no less brutal struggle in virtual space, something like a “Third World War” between different governments by means of hacking, DDoS attacks, disinformation, and all the instruments of modern information technology. At the same time – if we extend the definition of “violence” to all forms of coercion, and we seem to have good reasons to do so –, even within Western societies, a sort of intellectual or verbal violence is becoming the order of the day, rejecting former ideas of consensus in the name of social justice: “No peace without justice” as a well-known slogan of 2020 demonstrations have aptly put it.

In a situation like this, clearer principles are needed to deal with the issue of violence, be it actual or virtual, physical or intellectual. It seems strange at first sight to turn to the tradition of Christian political thought for such principles, for many contemporary Christians live in the profound conviction that Christianity rejects all forms of violence, but the truth is the exact opposite. Without ignoring the complexity of the problem, the Christian tradition has always formulated answers that were neither pacifistic nor warlike in any extreme sense but represented a sober middle way between the two.

The theory of just war

Has it ever been permissible for Christians to wage war? The historical answer to the question seems obvious enough: wars were ubiquitous in medieval Christendom, and some of those wars, namely the crusades, were not only “permitted” but commanded by the head of the Christian church, while the warriors themselves were called “God’s soldiers” (milites Dei).  In 2003, however, more than 700 years after the last crusade to the Holy Land (although there were other, local ones of lesser magnitude until the 17th century), it was the Pope himself who tried to convince George W. Bush to abandon his plans for attacking Iraq (Wills, 2004).  But was it because John Paul II was a pacifist, or was it because his idea of “just war” differed from that of the American president? The majority of American Catholics who voted for the Republican Party supported the attack as a typical case of just war, and since the very idea of just war has always been an integral part of Christian political thought, it seems reasonable to go back to the roots of this idea.

The thought that some wars were “just” and others “unjust” was not an invention of Christian thinkers, of course. Already in ancient Rome, leaders had to justify their military operations by different political and religious means (which were not two different things in ancient societies, of course, but rather two sides of the same politico-religious coin). Before a war, a long diplomatic process was required, then a ceremony performed by the so-called fetialis clergy, during which a priest had to declare war by the ritual throwing of a spear.

This well-regulated ritualistic tradition, however, went out of fashion by the 3rd century BCE, perhaps because of the independent military activities of local authorities and army commanders. As the German historian Klaus Martin Girardet points out, it was exactly the appearance of such “unjust” or “illegal” wars (bella iniusta) that prompted Cicero to outline a more circumscribed concept of just war, even though he never went as far as to create a comprehensive theory, only listed some of its criteria in his different works (Girardet, 2007).

Cicero’s considerations are nevertheless more than just historical curiosities. His De re publica (sometimes translated as The Republic, sometimes as On the Commonwealth) makes the very powerful claim that “an optimal state will never start a war”; yet, as he adds, there are two exceptions. One is when the state must fulfill a contractual obligation (pro fide); the other when it fights for its own survival (pro salute). In any case, the primary condition is that the cause of war should be “just” (which means both morally and legally legitimate) and not arbitrary: something that responds to the injustice of the enemy (Girardet, 2007). What seems more problematic is that this “injustice” may as well be passive or merely potential: in this case, the prevention of a future unjust act may also serve as a cause of war. As Cicero’s De officiis (On Duties or On Obligations) confirms, the sole aim of any just war is to create “peace” in the broadest sense of the word, as a situation void of any injustice.

Before turning to Saint Augustine, the first great Christian just war theorist who was also deeply influenced by Cicero, a few words should be said about the alleged pacifism of early Christians. This pacifism was, of course, partly based on an expectation of the imminent return of Jesus Christ, and partly on the words of the Gospel: “But I say to you, offer no resistance to one who is evil. When someone strikes you on your right cheek, turn the other one to him as well” (Mt 5:39). Early Christian authors like Saint Justin Martyr also referred to the Old Testament, one of their favorites being Isaiah’s “They will melt down their swords into plough-shares, their spears into pruning-hooks, nation levying war against nation and training itself for battle no longer” (Is 2:4). Let us not forget, however, that the Gospels – and the Old Testament passages cited as its precursors – were only concerned with a sort of private ethics and not with political issues like military obligations. It was only at the end of the 4th century when Christianity became the official religion of the Roman Empire that Christians could no longer avoid giving a more detailed ethical response to the problem of such “necessary evils” as war. 

According to the Hungarian Jesuit Béla Somfai, the re-evaluation of war in the patristic age started with Saint Ambrose (Somfai, 1995). Before he was elected a bishop, Ambrose had served as a governor and military commander of Northern Italy, which explains his special interest in the topic. His main emphasis was on the struggle against barbarians, which he articulated not only as a political question but also as a defense of the Christian community, based on the rules of just war borrowed from Cicero.

Saint Augustine, who listened to Ambrose’s speeches for two years after he had decided to leave Manicheism and join the Catholic church, also had to realize that defending the now established church could no longer rely on the “when someone strikes you on your right cheek, turn the other one to him as well” principle (Mt 5:39), for it would mean the surrender of Christian society to its enemies. By that time, as Somfai argues, the security of the state could no longer be separated from the security of Christendom. That is why, in contrast to the pacifist stance of early Christians, Augustine turned to the justification of military profession in the Gospel of Luke:

Soldiers also asked him, "And what is it that we should do?" He told them, "Do not practice extortion, do not falsely accuse anyone, and be satisfied with your wages" (Lk 3:14).

If the Holy Scripture had condemned all forms of war, as Augustine argued, it would have made it more explicit that even being a soldier was against divine law. However, the very phrase “be satisfied with your wages” implies that soldiers were not expected to give up their profession. In addition, Augustine was also aware that the Old Testament was full of wars waged on divine command, which were thus not only “just” but “holy” in the sense that it helped the chosen people to overcome enemies. Holy wars, however, belonged to the history of the Jews, and that is why Augustine’s main concern was the idea of just war that proved to be remarkably “secular” in the sense that it only implied the avengeance of injustices.

Therefore, as Girardet says, the just war theory of Augustine “contains no specifically Christian elements” (Girardet, 2007, p. 4); its criteria may even be completely deduced from Cicero. In contrast, the Hungarian philosopher Dániel Schmal maintains that the theory is not a “list of criteria”, but a description of the “ontological essence” of the civitas terrena (the “earthly city”). Because of the Fall, conflict, and war have become part of our human society, presenting a political issue that is at the same time theological: a fundamental element of separating the actual earthly city from the ideal city of God (Schmal, 1994).

During the Middle Ages, the concept of just war remained an integral part of Christian political thought. The Decretum Gratiani (the collection of Canon Law attributed to the Italian jurist Gratian) in the 12th century cited Augustine’s texts as well as papal decrees on war; authors like Albert the Great, Henry of Ghent, Godfrey of Fontaines, and many others – virtually all theologians – offered detailed justifications of war in the context of moral theology; until Saint Thomas Aquinas simplified the criteria in his Summa Theologiae (2a2ae, q. 40). In his account, just war required a legitimate authority (a king or the Pope), a just cause (self-defense or the punishment of injustices), and a right intention (proper self-conduct during warfare).

The late scholasticism of the 16th century added a further element to the discourse of just war. Francisco de Vitoria and Alberico Gentili were the first to consider the possibility that both parties in a conflict may wage a just war. The historical situation of Vitoria is especially significant for he wrote during the Spanish colonialization of America. His stance may even be called “revolutionary” in the sense that he first made it explicit that religious difference (in itself) could not be a just cause of war (see his De iure belli or On the law of war, 1532). In a technical sense, however, he only followed the classical criteria of legitimate authority, just cause, and the behavior of Christians in war.

The first period of just war theory was closed by Hugo Grotius and his De jure belli ac pacis (On the Law of War and Peace) in 1625. Although Grotius relied partly on Christian sources, he introduced a thoroughly novel concept of just war. The criteria were reduced to two: first, an effective cause was needed (the person whose interests were at stake: an individual in a private war, or a public authority in public war, most likely the sovereign); and second, that this authority officially declared war. In the first case, a – however faint – Christian influence is still recognizable, while in the second, according to Girardet, there is no connection either to the Ciceronian or the Christian tradition. As we have seen, however, the official declaration of war was already part of Roman customs, and Grotius himself refers to Cicero in this respect. So much seems nonetheless true that abandoning the criterion of just cause established the “sovereign states’ purely formal right to wage war without any moral constraints” (Girardet, 2007).

The theory of just war gained new impetus in the twentieth century with the publication of Michael Walzer’s Just and Unjust Wars (1977), later followed by Arguing about War (2004). In these works, the Jewish-American political philosopher goes back to the religious tradition that formed Western politics and morals. He mainly concentrates on the work of Maimonides, Saint Thomas Aquinas, Vitoria, Suárez, and Grotius, while also making some references to Saint Augustine. Walzer’s definition of just war can be summarized in two brief propositions: “that war is sometimes justifiable and that the conduct of war is always subject to moral criticism” (Walzer, 2004, p. ix). This way, the theory of just war takes a middle ground between pacifism and realism. Pacifists reject the first proposition (that war, at least in some cases, can be just) thinking that war is a crime in itself; while realists deny the possibility of any moral criticism, saying that laws are silent during times of war.

As can be seen from this brief summary, the pacifism of ancient Christians was soon replaced by the conviction that – under specific circumstances – war can be justified, and this would become the mainstream view of the great Christian churches for about one and a half millennia. During the 20th century these two traditions – ancient Christian pacificism and the Christian theory of just war – appeared once again parallelly, which leads us closer to a solution of the contradiction outlined in the beginning.

In the middle of the 20th century, Pope Pius XII narrowed the list of just causes down to one, that of self-defense against aggression. The horrors of World War II and the failures of peace mediations made the Pope condemn all offensive wars in his 1944 Christmas message (Somfai, 1995, p. 326), meaning the Pope did not entirely preclude the possibility of just wars; during the 1950s he went as far as to acknowledge that “even in the present-day circumstances war cannot be considered illicit for a nation to efficiently defend itself and to achieve victory when it is attacked unjustly and all efforts to avoid it have proved futile” (quotes Bateman, 2019). He did declare, nevertheless, that nuclear weapons could not be employed within the boundaries outlined by St. Augustine’s writings on just war theory (Bateman, 2019). In other words, while the Pope – inspired by his own experience – made considerable efforts to promote peace, and carefully distanced himself from some elements of the tradition, he also did not return to the pacifism of early Christianity but chose to adapt the just war theory to his own historical epoch.

The issue of nuclear weapons was also taken up by his successor, Pope John XXIII, whose encyclical letter Pacem in terris explicitly said that “in this age which boasts of its atomic power, it no longer makes sense to maintain that war is a fit instrument with which to repair the violation of justice” (Pacem in terris, 127). All this would have allowed the Church to gradually move away from the whole tradition of just war, which was what many observers expected from the Second Vatican Council. As Somfai says, the theoretical recognition of the pacifist standpoint would have actually “restored the full richness of the Christian tradition” (Somfai, 1995, p. 327). However, the Council once again reaffirmed the principle of self-defense as a possible just cause, and although this move may be interpreted as a compromise which intended to replace the “negative” definition of peace (the absence of violence) with a “positive” one (an order of love and justice), it still does not mean “pacificism” in Walzer’s sense of the word. In other words, like in many other cases, the Council aimed to represent a dialectic of innovation and conservation at the same time.

This may be the root of controversy between the American Catholics’ opinion and that of the Pope during the Iraq war. However, as Garry Wills’ article suggests, there can be no real contradiction here, since both belong to the richness of the Church’s tradition. As the American Bishops’ Conference put it as early as 1983, pacifists and just war advocates “both find their roots in the Christian theological tradition; each contributes to the full moral vision we need in pursuit of a human peace. We believe the two perspectives support and complement one another, each preserving the other from distortion” (The Challenge of Peace, 121).

Yet, although it is a doubtless brilliant rhetorical move to speak of mutual support, it would be better to adhere to the original meaning of concepts, and accept that for much of the Church’s history, just war theory primarily addresses the issue of violence; unless we want to get entangled in such dubious language games as calling the latter a form of “conditional pacifism” or something like that.

The chances of clarifying conceptual unclarities are rather weak. The encyclical Fratelli tutti issued by Pope Francis in October 2020 lays great emphasis on the problems of war, rejecting practically all forms of it with a pacifistic zeal known from early Christianity. “Never again war!” – as it says, even adding in note 242 that the just war theory of Saint Augustine is something “we no longer uphold in our own day” (Fratelli tutti). At the same time, however, it leaves open the possibility that it is only a specific type of just war (that of the Augustinian classification) that is rejected, and not the whole just war tradition as such.

Pope Francis on wars

It is therefore worth stopping for a moment and analyze the alleged conflict between Pope Francis’s statements presented in Fratelli tutti and Augustine’s concept of “just war”. In what context does Pope Francis write about just wars? And what does he exactly write about it?

Pope Francis touches on the question of wars several times in his encyclical, but there is a part (from article 255 to 262) that focuses directly on wars. Pope Francis writes that war is a constant threat to the world. He also adds that some people seek solutions in wars, and although in some cases, it might seem that war solves the problem, it does not. Moreover, it also brings new elements of destruction to the world. Pope Francis – among other aspects – highlights the horrible outcomes of wars, points to its globalized nature, and calls special attention to the victims of wars. He also adds that in our world, because of nuclear, chemical, and biological weapons, we have a power we never had before, and there is no guarantee that it will be used wisely. The encyclical wishes to show Christians that war is a failure of politics; it has miserable effects on humans and should not be treated as a solution for any existing problem (Fratelli tutti, 255-262).  

The most significant part of the encyclical in this regard is article 258. Here, Pope Francis reminds the reader that every war has been “justified” in recent decades by humanitarian, defensive, precautionary, or other excuses. After that, he adds: “We can no longer think of war as a solution because its risks will probably always be greater than its supposed benefits. In view of this, it is very difficult nowadays to invoke the rational criteria elaborated in earlier centuries to speak of the possibility of a ‘just war.’ Never again war!” (Fratelli tutti, 258).

The first sentence of the citation seems to be the most relevant part in the light of just war thought. More precisely, the first part of the first sentence, since the second one contains the word “probably” which does not make it weightless but significantly softens the argument. What does “we can no longer think of war as a solution” mean?  Does it mean that Christians cannot participate in wars? Most likely, it does not. First, it refers to “thinking” of war and not to the fact of participating in war per se. So, although it might seem controversial to participate in a war that is not thought of as a solution, this sentence does not explicitly prohibit Christians from participating in a war. Second, it is worth looking at the context as well, because Pope Francis repeatedly focuses on the fact that most recent wars were claimed to be a solution to a problem (the reader is quickly caught thinking of America’s “just” war on terror). So, although it can be argued that Pope Francis questions the efficiency of usual causes for just wars, his main concern is that the justification of war is usually just an excuse. This line of thought is supported by the fact that Pope Francis writes the following: “The Catechism of the Catholic Church speaks of the possibility of legitimate defense by means of military force, which involves demonstrating that certain ‘rigorous conditions of moral legitimacy’ have been met” (Fratelli tutti, 258). The encyclical does not contradict this statement, only highlights that it can be interpreted broadly in several cases, which would provide an excuse for war.

The second sentence is once again somewhat permissive: it uses the word “very difficult,” meaning that it is not impossible. Moreover, the word “nowadays” is added, which might even suggest that at other times it was not very difficult to find a rational criterion for waging a just war.

The last part contains the statement “Never again war”. Although it might be seen by some as the capsulized form of Pope Francis’s opinion, it is not necessarily related to the theory of just war. Rather, it is a call for Christians that is very radical (perhaps even utopian) in content and very rhetorical in style. This part also shows that encyclicals function mainly not as scientific elaborations of subtle theological topics but rather as messages to serve as an orientation for believers in contemporary issues. Therefore, this part should not be viewed as a detailed theological or philosophical reflection on just war theory. From the perspective of political philosophy or just war theory, the interpretation of Pope Francis’s ideas might seem somewhat problematic; yet taking into account Pope Francis’ aims, the genre of encyclicals, the context of the present document, and the content of its arguments, it sufficiently serves its purpose.

The last – and in this case, most exciting – part of the encyclical is the aforementioned 242nd note which mentions “Saint Augustine, who forged a concept of ‘just war’ that we no longer uphold in our day.” Unfortunately, this part is not developed further by any argument or reference to another document that would explain why Augustine’s concept of just war (or which part of it) is no longer suitable for us. So, although the passage seems to imply that there is a conflict between Augustine’s and Pope Francis’ teaching, insofar as the latter is more restrictive – which is obvious from the analyzed parts (article 255-262) of Fratelli tutti, the exact difference remains obscure.

To sum it up: Pope Francis’s position could certainly be labeled “idealist” or “utopian” either by scholars (especially realists) or by practicing politicians. It is also obvious that his primary intent is to prevent wars and to narrow the possibility of finding a just cause for war, as he is highly skeptical about the possibility of finding a just cause for war nowadays. Compared to the realist school and the representatives of Christian just war thought, his position stands closest to that of the early Christian pacifists. Yet, in at least two ways, he also differs from them. First, he does not claim that there is no just cause for war, after all. Second, he is much more interested in worldly matters like human suffering or well-being (the human condition itself) than any of his predecessors.

Realism in international relations

Beside Christian just war thought, there is another highly influential approach to the issue of war in international relations theory: the realist or, more strictly speaking, the political realist approach. According to the Stanford Encyclopedia of Philosophy, realism or political realism, “is a view of international politics that stresses its competitive and conflictual side. It is usually contrasted with liberalism, which tends to emphasize cooperation” (SEP, 2017). The political scientist Allison McQueen summarizes political realism in another way and claims that it is “a tradition that is focused on power and interest, suspicious of moralizing, and attentive to the limits of political action” (McQueen, 2018, pp. 6-7). The political realist tradition is quite heterogeneous; it consists of ideas from Thucydides, Augustine, Machiavelli, Hobbes, Marx, Weber, and Schmitt (McQueen, 2018).

Based on different elements (e.g. the main actors, the actors’ primary motivations, the possibility of ethics), several realist schools and traditions have appeared in the IR literature. Some scholars put their emphasis on the “old” realists (e.g. Thucydides, Machiavelli, and Hobbes); others focus on twentieth-century classical realists (e.g. Morgenthau and Niebuhr); while neorealists or structural realists (e.g. Waltz and Mearsheimer) and neoclassical realists (e.g. Rose and Zakaria) also remain highly influential. 

It should be clear, however, that – despite what authors like Michael Walzer suppose – realism does not represent an altogether amoral view of politics. The position that abandons all moral considerations in politics (and thereby eliminates the concept of politics in all of its traditional senses as well) is rather called Realpolitik. According to Matt Sleat, Realpolitik can be understood as a “reduction of politics to violence by making the de jure right to rule equivalent to the de facto ability to do so” (Sleat, 2014, p. 315). The “might makes right” slogan fits well with this view. Political realism, in contrast, tries to keep its distance from Realpolitik; even though its representatives want to ensure greater autonomy for politics and are skeptical towards the moral capacities of humans and human communities, they never treat politics as a fully amoral sphere.

The intersections of realism and Christian just war thought

In this paper, we are primarily dealing with classical realism, and although it focuses on other aspects of international relations, it is not far from Christian just war thought. Some scholars who belong to classical realism were eager Christians themselves and wanted to find a way to face idealism or moralism in international relations. Moreover, their thought is – to varying degrees – connected to the father of the just war thought, Augustine. But anyhow, who are these classical realists?

The representatives of classical realism are mid-twentieth century American authors; their leading figures were Reinhold Niebuhr and Hans Morgenthau. The American IR realists tried to employ the insights of the political realist tradition in twentieth-century international politics (Bell, 2009). Moreover, these representatives of classical realism summoned Augustine’s realistic views on human nature and relations to underpin their assumptions regarding twentieth-century international politics. The classical realists agreed on Augustine’s two central premises. Just as Augustine, the classical realists focused on human nature. Human nature in their view determined human deeds, and human deeds defined human relations (including international relations). Furthermore, though not as much as Augustine, classical realists were pessimistic towards human beings’ moral capacities. Yet, besides these similarities, why was Augustine so essential for them?

First, in an era of extreme idealism and realism, they found that Augustine highlighted the sinfulness of humankind while not abandoning man’s capacity for justice (Eyster, 2010). Second, in a century of two world wars, Augustine’s just war tradition offered a middle way between pacifism and realism (Charles & Corey, 2012). It meant that it was morally justifiable to participate in a war under certain conditions, which was crucial for several American Christians (like Niebuhr). Third, Augustine’s fifth-century descriptions regarding specific international relations phenomena were plausible related to the twentieth century. For instance, Augustine described the situation of the “security dilemma” (Elshtain, 1995; 2003). Although the renewed interest in the Augustinian tradition in IR was mainly due to Niebuhr (Jones, 2003), Augustine’s realistic views on human nature and human relations had in some way always been present in the heart of classical literature. This also means that Augustine’s work can be viewed as an intersection between classical realist and Christian just war thought. What both realists and just war thinkers reject is a “pure”, unconditional type of pacifism. But what are the cases for classical realists that would justify participating in a war? Do they formulate ethical expectations before entering the war? In the following section, Niebuhr’s and Morgenthau’s considerations connected to these questions will be summarized. 

Reinhold Niebuhr

In the case of Niebuhr, there is no doubt that he treated some cases of participating in war to be just. He never questioned that the United States was right to engage in two world wars. Niebuhr – just like Augustine – was not a dogmatic theologian or philosopher, so his views regarding just wars did not fit in any larger system and were changing over time, depending on the historical context. During the First World War, Niebuhr highlighted the necessary compromises to be taken to reach peace, even if that would result in a military intervention. In the Second World War, he forcefully supported anti-Nazi forces to prevent this new form of “paganism” from occupying the rest of the world. Therefore, there are already two cases that can justify a war: either to reach peace or to stop the world’s evil forces. But before placing Niebuhr in the Christian just war tradition, two supplementary notes must be made.

First, as Robert Paul Pappas highlights, Niebuhr criticized the predominant just war theory as a byproduct of the Catholic natural law tradition. Niebuhr’s concept of original sin refuted Catholic rationalism that made clear distinctions between just and unjust wars (Pappas, 2014). If there is a seemingly clear cause for just war, can we calmly participate in it? According to Niebuhr, we should doubt our own decisions as it is usually – maybe even hidden behind an ideology – supported by our sinful self-interest. Pappas quotes Niebuhr when he writes that history testifies that not all “wars are equally just and not all contestants are equally right. Distinctions must be made. But judgments which we make are influenced by passions and interest, so that even the most obvious case of aggression can be made to appear a necessity of defence” (quotes Pappas, 2014, p. 102).

Second, Niebuhr – thanks to his realism – viewed wars as situations that change power relations. There are cases when the balance of power is shaken, and the dominant force evolves into a tyrannical one. In certain instances (e.g. Indochina in the Cold War) power must be faced by power; the aggressor must be contained. In summary, Niebuhr’s just war thought had some core ideas but was more contextualist. He argued that there were cases that might invoke just (or more just than unjust) wars, but participants should always be aware of their sinfulness. If it is revealed that their sinfulness fuels the war, they should stop it. For instance, Niebuhr demanded American forces to stop the cruelties in Vietnam and have the army withdrawn from the country.

Hans Morgenthau

Hans Morgenthau was not a just war theorist. He was a central figure of the classical realist school in IR and – as an academic – he was more descriptive than prescriptive. It is nevertheless possible to define Morgenthau’s ethical considerations; and from those, we might understand how he saw wars.

Sean Molloy argues that – following the footsteps of Aristotle and Epicurus – Morgenthau’s central notion is doing the lesser evil. The core question of this approach is: “how must a moral person act in the political sphere?” Morgenthau writes the following: “the best he can do is to minimize the intrinsic immorality of the political act. He must choose from among the political actions at his disposal the one which is likely to do the least violence to the commands of Christian ethics. The moral strategy of politics is, then, to try to choose the lesser evil” (quotes Molloy, 2009, p. 99).

From this passage, it becomes clear that the best option in politics is to do the lesser evil. One must recognize the evil and accommodate it – says Morgenthau. Political ethics is the ‘ethics of doing evil”, but the quality and the quantity of the evil are not equally involved in the decisions; one must try to choose the lesser evil. Morgenthau highlights particular virtues that are long lost from twentieth-century politics: for instance, prudence, moderation, and the ability for a politician to view himself (with his fate and actions) from a historical perspective and not just from the viewpoint of daily politics. Morgenthau’s moral philosophy is very different from most theorists since, just like Aristotle, it focuses on applying intellect in certain situations according to context and capability instead of following a universal law derived from an abstract principle or expedience (Molloy, 2009).

There is a clear case, Vietnam, and an alleged case, Iraq, when Morgenthau was against the war, though the “outcome” of his thought is less relevant from this paper’s perspective. The significance of Morgenthau here is twofold. Although he is far from being a just war thinker, even in his lesser evil method, he explicitly referred to the importance of Christian ethics. Second, following Aristotle, he emphasized human intelligence, prudence, and moderation before making a political decision. This consideration might be a useful contribution to the Christian just war thought as well.


It may be seen, Christianity’s contribution to the issue of warfare, its justification, and its rules of conduct can hardly be overestimated. Apart from a relatively brief historical period when Christians were not in the situation to take responsibility for the affairs of the state - pacifism has never been supported by the Catholic Church or later by the mainline Protestant churches. Let us repeat once again that pacifism – contrary to some vague everyday usage – does not simply mean a wish for peace, but a radical rejection of all forms of war or violence, even in the case of self-defense or fighting for a good cause, for example, national independence or social justice. In this sense, pacifism is indeed an apolitical or rather antipolitical attitude, and that is why it remains difficult to adopt for those large Christian churches that take responsibility not only for themselves and their adherents but also for the societies they live in. Although it is true that some Protestant denominations have always taken a radical pacifist stand, these also openly profess a sort of Christian anarchism as well. Just war theory, on the contrary – and even realism in its more sophisticated sense, which is not the same as a “might makes right” Realpolitik – keeps taking a sober middle ground between promoting peace on the one hand, but also accepting the sad fact of the human condition that sometimes you have to fight for what is right. Just war theory will thus remain a part of our world as long as violence remains a part of it. It will, of course, also change with it, and the next interesting issue will perhaps be whether just war theory can be extended to the point to become applicable to non-physical forms of violence. For whether or not the number of traditional wars, revolutions, or terrorist attacks will continue to decline, the amount of virtual, intellectual, or verbal violence is already steadily growing; but this is already beyond the scope of this analysis.

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