Jus Post Bellum and the Decision to Withdraw from Afghanistan

Abstract

This article makes moral sense of the Western withdrawal from Afghanistan in 2021. It does so by applying classical just war thinking. The classical bellum justum, it argues, can make a distinctive contribution toward evaluating the decision to leave Afghanistan, a decision that continues to be discussed controversially. The article points out that classical just war thinking did not introduce distinct moral categories beyond jus ad bellum, such as jus in bello or jus post bellum. Exactly because classical just war thinking was meant to apply to all phases of a war, the article goes on to argue, it provides important lessons for just war as a tool of statecraft that seeks to inform political decision-making. Applying the wisdom that is encapsulated in the classical bellum justum to the withdrawal decision in Afghanistan, the article, although it is critical of its execution, generally sides with the Biden administration's course of action.

Keywords:

• Catholic social thought
• just war
• Thomas Aquinas
• statecraft
• international relations
• Afghanistan

More than one year after the event, the photos of the August 2021 Kabul airlift have gained an almost iconographic status. At the time, no person of good will could remain indifferent to the fate of those having to fear the Taliban's return to power. Today, as the Taliban rebuild their human rights abusing regime and many Afghans face persecution and hunger, the West's soul-searching about the decision to withdraw continues. Although the ongoing war in Ukraine is now the number one political issue of the day and the situation in Afghanistan has moved to the background of media attention, the withdrawal decision will continue to be controversial. In a few years’ time, the chaos and desperation captured in photos from Kabul Airport will probably overshadow the hopeful images of girls who had a chance to go to school in the years prior. In a sense, the hasty pullout from Afghanistan has become a symbol of the limits of Western power with implications for further theaters of foreign engagements in similarly hostile environments, such as Mali. It also invites serious soul-searching among those who were directly involved in the war in Afghanistan, including thousands of soldiers and civilian aid workers. Have the 20 years in Afghanistan been in vain? Was there not a moral responsibility to stay and prevent the Taliban takeover?

In order to answer these questions, just war thinking can provide unique insights. For centuries, just war thinkers have sought to grapple with the ethical questions war tends to provoke. One aspect of armed conflict that has received considerable attention over the last decade and a half is the justice after war, or jus post bellum. A main concern of jus post bellum thinking that is of direct relevance to this article has been to investigate the responsibilities the victorious state, or coalition of states, acquire(s) after defeating the enemy. Importantly, by introducing a new term to the moral vocabulary and proposing detailed rules for post-war conduct, today's jus post bellum reasoning differs from the classical just war. The classical bellum justum, succinctly summarized in the work of Saint Thomas Aquinas, did not introduce distinct categories beyond jus ad bellum (the right to go to war), such as jus in bello (right conduct in war) or jus post bellum. In this article, I argue that the classical bellum justum, exactly because it was meant to apply to all phases of war—before, during and after—can teach us important lessons about the war in Afghanistan. It can thus help us make moral sense of the difficult challenges the war presented to political leaders as well as guide the right course in the years ahead. Crucially, bringing to bear the insights of the classical bellum justum on the matter of post-war justice does not necessarily mean that aspects that may strike some as wrong today, such as the use of armed force for retribution's sake, need to be adopted. Put differently, this article starts from the assumption that there is meaning to be found in engaging with the classical just war, without seeing it as the be-all and end-all.¹ The classical bellum justum can help us in our understanding of the moral problems we face today, including the withdrawal from Afghanistan.

The Classical Just War

The classical idea of just war was about providing answers to the question of when a ruler would be justified to use armed force. In order to find these answers, the just war criteria of just cause and right intention were meant to inform the ruler. Thomas Aquinas (1948, II–II, q. 40, a. 1) provided a succinct systematization of the classical understanding of just war in his influential Summa Theologiae.² Importantly, as James Turner Johnson (2014, chap. 2), the pre-eminent historian of the just war tradition, has argued, it was by no means a coincidence that Aquinas discussed the authority criterion first. St. Thomas emphasized the ruler's responsibility for establishing what Johnson refers to as the three “ends of good politics,” namely, those of order, justice, and peace. Consequently, because only the ruler was entitled to decide on the matters of just cause and right intention, legitimate authority was the primary just war criterion. It was logically prior to the just cause and right intention criteria. Following from this conceptualization, the ruler's authority to employ armed force was inseparably linked to his/her responsibility for the common good. Moreover, there was an additional theological rationale that foregrounded the distinction between war and the illicit private use of force. Whilst war waged for the common good could be an act of charity, of rightly directed love, private uses of force beyond immediate and proportionate self-defense would be the expression of wrongful selfishness, of illicit self-love. Crucially, the common good that is important to the classical understanding of bellum justum came in two forms. In the first place, there was the common good of the ruler's own political community. At the same time, however, there was also the common good of all mankind. As a result of these two forms, maintaining and establishing order, justice and peace could require the use of armed force both within and beyond one's own territory. In contrast to the modern understanding that hinges on the principles of political sovereignty and territorial integrity, for the classical bellum justum, there was no absolute sovereignty that would rule out a forceful response in the light of grave abuses of natural law. Thus, rulers had to accept certain limits of authority within their own territories and, simultaneously, had some say in the internal affairs of neighboring rulers.

Just Cause

Today's just war thinking as well as international law concentrate on defensive uses of armed force. This modern near-consensus abandons the classical understanding that accepted self-defense as just cause, but foregrounded retribution instead.³ In essence, bellum justum was a means to re-establish a state of justice that had been disrupted by prior wrongdoing. The contemporary limitation of just cause to primarily self-defense is undergirded by a changed understanding of political authority as well as prudential considerations. Enshrined in the Westphalian settlement, this new understanding did no longer consider the ruler as a divinely instituted avenger of justice. After the treaties of Münster and Osnabrück, the ruler was commonly seen as the representative of the people only, who took responsibility for the people's fundamental right of self-defense. This new understanding of sovereignty, moreover, limited the ruler's responsibility for the common good to the people entrusted to him/her within a defined territory. This was an important change, as the earlier understanding had also emphasized the common good of all mankind. As a result, the Westphalian principles of political sovereignty and territorial integrity effectively replaced the previous responsibility for the common good of all mankind which, in principle, allowed for intervening in other rulers’ affairs in response to injustice. Furthermore, the desire to stop rulers from intervening in each other's affairs over the issue of religion contributed to the limitation of just cause to self-defense. Several centuries later, the experience of modern warfare and the destructiveness of modern weaponry contributed additional prudential concerns, which resulted in the UN framework and just war thinking's contemporary near-consensus about self-defense as the only just cause for war.⁴

Right Intention

The criterion of right intention has not been at the center of attention in most contemporary accounts of just war. In this neglect, the modern understanding deviates another time from the classical understanding. Aquinas held that intention in war shows in belligerents’ war aims and how they fight to achieve these objectives. That is why St. Thomas cautioned against the negative passions which can arise on the battlefield. Such a virtue approach implies restrictions on conduct in war, but Aquinas did not develop detailed rules as, for example, were present in canon law or the code of chivalry.⁵ Aquinas distinguished between the cardinal virtues of justice, prudence, fortitude and temperance, and the theological virtues of faith, hope and charity. The most basic difference between these two types of virtue is that the cardinal virtues provide the necessary foundation for human action on earth, for imperfect happiness, while the theological virtues point mankind to its supernatural end of beatitude. For just war thinking, the cardinal virtue of prudence and the theological virtue of charity take on a crucial role. Prudence St. Thomas (ST, II-II, q. 47, a. 2) defines as “right reason applied to action.” With regard to just war, this cardinal virtue is crucial for political and military decision-makers who oftentimes need to choose between various possible alternatives of action.⁶ The cardinal virtues like prudence are transcended by the theological virtues, as they lead human beings to their final end, which is unity with God. Importantly, St. Thomas discussed the question of just war within his treatment of charity and his thought is directed toward the endpoint of human existence. However, taking divine charity as the lodestar of human action does not do away with the need of meting out justice in this world. Whilst for Christians the ultimate telos is the eternal happiness of God's kingdom, bellum justum may contribute to an approximation of that kingdom imagined as peace on earth. Therefore, the use of force remains morally justifiable, although Christians must never forget the final goal of overcoming violence.

Jus Post Bellum

As noted earlier, in today's just war debate, jus post bellum has become a major field of study. Over the last 15 years or so, especially after the experiences of Iraq and Afghanistan, an entire body of academic literature has been developed.⁷ Commonly, jus post bellum scholars imagine just war as unfolding within a three-step framework. Firstly, there is the jus ad bellum, the decision to go to war. Secondly, there is the conduct of war, the jus in bello. And, then, thirdly, there is the jus post bellum, the phase after the end of the war. These thinkers argue that whilst much attention is being allocated to jus ad bellum and jus in bello considerations, the question of moral responsibility after an armed conflict has ended has not yet received the attention it deserves. That is why they propose rules of conduct that should govern the post-conflict behavior of the victorious state.⁸

Generally, there are two basic approaches to jus post bellum: a minimalist and a maximalist approach (see Bellamy 2008). The former approach is mainly interested in restraining the victorious state. Its focus is on exploring the permissions the victor holds vis-à-vis the defeated party. In contrast, the maximalist position's primary concern is not the permissions of the victor but the moral obligations toward the defeated party after the war has ended. It seems fair to argue that the maximalist position has received most attention from just war theorists. Arguably this has been the case due to the soul-searching the post-9/11 wars in Afghanistan and Iraq have caused. There seems to be a direct connection between the increased interest in jus post bellum and the difficulty to stabilize Iraq and Afghanistan after what had initially appeared to be relatively smooth military campaigns that toppled Saddam Hussein and the Taliban regime respectively. However, as I will argue below, the increased interest in post-war justice and the jus post bellum stream it has facilitated has further compartmentalized the field of just war. As I noted above, the classical just war was undergirded by a holistic understanding that did not spell out distinct principles of jus in bello, nor did it come up with detailed jus post bellum criteria. Crucially, that was not at all a sign of underdevelopment. Rather, it can be seen as the expression of a conviction that the decision to employ armed force is a very complex one that must be considered holistically. I am under the impression that in much of contemporary just war thinking this holistic nature of the framework has been lost. Therefore, my contribution to the scholarship on post-war justice in the context of Afghanistan will be to highlight the importance of seeing the decision to use armed force in all of its phases, which is part of the responsibility for the common good held by those in authority.

Following from my holistic understanding of just war the thinker whose jus post bellum argument is most relevant to this article is Eric Patterson.⁹ That is because Patterson grounds his work in an engagement with the classical just war tradition. Patterson (2012b, ix) proposes what he calls “a parsimonious framework” that is built around three criteria: order, justice and (re)conciliation. Based on his interest in the classical bellum justum it is no coincidence that his post bellum criteria correspond to the three ends of good politics that underpinned Aquinas's understanding of just war. What shines through in Patterson's conceptualization is the understanding of just war as a tool of statecraft as found in Aquinas. It does not surprise then that Patterson advocates a parsimonious account, as any case will be different and decision-makers need to apply the jus post bellum criteria prudently. For example, Patterson argues that retribution is an important objective after war. However, the criterion of justice may conflict with the criteria of order and conciliation. In other words, seeking rights vindication may come at the cost of political disorder and hinder conciliation. When that is the case, it might be prudent not to engage in acts of retributive justice that might endanger order and conciliation. Crucially, linking back to just war as a tool of statecraft, such decisions are only to be taken by those in authority who are responsible for the common good. In my following analysis of the withdrawal from Afghanistan the three ends of good politics that shape Patterson's jus post bellum will function as the guiding principles of my argument. That said, I will argue throughout that Aquinas's comprehensive understanding of just war, against the contemporary tendency in just war to compartmentalize the framework, is best able to make moral sense of the withdrawal decision.

Having provided a brief overview of contemporary jus post bellum scholarship, let me spell out my own conceptualization of post-war justice. As already noted above, my understanding differs from that of most contemporary jus post bellum thinkers through my emphasis of the holistic nature of just war. I am of the opinion that compartmentalizing the ethics of war into distinct domains can be problematic. I think that each case is unique and, therefore, highly developed lists of post-war obligations may conflict with realities on the ground. I also think that by concentrating on jus post bellum as a distinctive phase of conflict, the wisdom of the classical just war as being applicable to the entire spectrum of the use of force can get lost. In other words, I hold that the succinct summary of bellum justum provided by Aquinas can do a better job at helping us grapple with the aftermath of war, because it never loses the focus on the ruler's responsibility for the common good of his/her own political community and that of neighboring communities. It may also remind those in authority that just war reasoning applies to all phases of a conflict and a change in circumstances may turn a previously justifiable war into a morally indefensible undertaking. Last but not least, just war imagined as a tool of statecraft and the attention it gives to prudential considerations as enshrined in the right intention criterion calls upon decision-makers to weigh their responsibilities in service of the common good carefully. That is where the so-called prudential criteria of just war, criteria Aquinas did not develop specifically, come in. These considerations include the proportionality criterion (the idea that the expected outcome of the war must be proportionate to the harms it inflicts), the last resort criterion (the idea that war must only be waged when the viable non-violent pathways have been considered), and the criterion of reasonable hope of success (the idea that war must only be waged if the cause is not futile).

So what exactly is the place of jus post bellum within the classical framework? Just as Aquinas did not develop a distinct category of jus in bello, there is no stand-alone discussion of jus post bellum in his work. I argue that this is for a deliberate reason. Classical thinkers applied bellum justum, as encapsulated in the three just war criteria, to the entire spectrum of the use of armed force. The ruler's responsibility for the common good of his/her own political community and that of neighboring communities included the establishment of order, justice and peace before, during and after the use of armed force. Importantly, with regard to post-war justice, the intended peace was not simply one of an absence of violence, but one that establishes and maintains a just order. As a result, the responsibility of the victorious ruler would not end with the declaration of military victory. As Johnson (2012) has argued, the ruler would also keep in mind his/her responsibility toward the defeated enemy and the international order in the aftermath of the war. In practical terms, this would require the acknowledgment that after a conflict armed force may still be needed to establish or maintain peace imagined as just order. The ruler would also be mindful of the fact that military means can only help establish a just peace. In the end, it is the defeated side that will need to take responsibility for the common good of its people. Ultimately, the task is a political, not a military one. At the same time, the victorious side must also deal with the inevitable questions related to the post-conflict environment: What is the price worth paying, both in blood and in treasure, in the attempt to foster a just peace after war? What if the commitment to post-war justice is starting to become a burden to one's own common good—materially and psychologically? When is it time to leave?

Going back to the initial idea of the authority to wage just war as grounded in the responsibility to one's own common good and that of the global common good, the answer seems clear. Primary responsibility is due to one's own political community. Essentially a natural law idea, the Thomistic argument is that some sort of self-sacrifice in the service of others is warranted but that there are limits. What those limits are depends on the details of the case at hand. Ultimately, it is a judgment call that only those in authority are entitled to make. In taking that decision, they are in need of a considerable amount of prudence, which, once more, emphasizes the nature of just war as a tool of statecraft.

Jus Post Bellum and Afghanistan

Having laid out the classical bellum justum and its relation to jus post bellum, what can we learn from Aquinas's conceptualization? One year after the Kabul airlift it seems safe to conclude that the hasty pullout and all of the immediate negative consequences it has caused was catastrophic. Most ethicists will also agree that there is a responsibility to help those Afghans who worked with Allied troops and are now in mortal danger. The fact that many of these people have been promised to be evacuated but now find themselves trapped in Afghanistan sheds a dark light on Western foreign policy. Personally, I would go beyond that, arguing, as the The Times (2021) has put it, that there is a “moral duty to extend aid to Afghanistan” in order to avoid a humanitarian disaster, especially mass starvation. We may not like the new regime, but if we can help those in need by supporting, for example, the World Food Program, it is the right thing to do. Relatedly, there seems to be a responsibility to unfreeze the money held back by the United States in order to help the needy in Afghanistan. Of course, this responsibility needs to be weighed against the Biden administration's concern that the $3.5 billion that are still held back do not fall into terrorists’ hands (see Baker 2022). On this question, the suggested international trust fund might function as a viable solution that should be explored further.

Despite making these suggestions for the way ahead, in this article, I am mostly interested in the decision to leave Afghanistan as such, the big picture if you will. Before I turn to that picture, however, I need to address the relationship between means and ends in classical just war, which is highly relevant to the criticism of the hasty pullout noted in the previous paragraph.¹⁰ In order to do that, let me refer to St. Thomas's thinking on “the good and evil of human acts.” Although his treatment of this issue is not discussed in the section on war specifically, the argument he makes applies to all human action, including armed conflict. Aquinas (ST, I-II, q. 18, a. 4) holds that the means used to achieve a good end must be evaluated in order to rule on the justifiability of the end:

Nothing hinders an action that is good (…) from lacking goodness in another way. And thus it may happen that an action which is good in its species or in its circumstances is ordained to an evil end, or vice versa. However, an action is not good simply, unless it is good in all those ways: since “evil results from any single defect, but good from the complete cause,” as Dionysius says (Div. Nom. iv).

Applying St. Thomas's argument to the withdrawal from Afghanistan, clearly, the mistakes that were made in its execution cannot be separated from the morality of the overall decision to leave the country. A year after the withdrawal it seems fair to conclude that more should have been done to avoid the chaos that unfolded in the summer of 2021. There had been more than enough voices who unsuccessfully pushed the Biden administration to put more effort into fostering a political settlement between the Afghan government and the Taliban, including senior US military leaders and its NATO allies.¹¹ Perhaps, a third-way option should have been attempted by making a complete pullout conditional to an intra-Afghan peace settlement.¹² In fact, the failure to integrate the Taliban into the Afghan government has been identified as one of the major early mistakes that were made after the successful invasion. Carter Malkasian (2021, 456) argues that the Bush administration's failure to follow “Churchill's advice of magnanimity in victory” vis-à-vis the Taliban sowed the first seeds of defeat. In this regard, Patterson's jus post bellum principle of conciliation comes to mind. All of that said, however, I am of the opinion that, although means and ends cannot be discussed in isolation, the controversies associated with the decision-making on how to leave do not make the decision to withdraw as such unjustifiable.

Having engaged with the means briefly, let me now turn to the end that is the focus of my moral argument, namely, the overall decision to end the war in Afghanistan. Essentially, the way I understand President Joe Biden's (2021) justification to leave Afghanistan, is that he made the argument that after more than two decades of self-sacrifice by the American people for the good of the Afghan people, it was time to concentrate on America's own common good. To use the worn-out phrase: “Let's do nation-building at home.” It was a mistake to move to what in jus post bellum terminology is a maximalist position, namely, the expansion from a counterterrorism campaign to an attempt at transforming the Afghan society.¹³ Even America's resources are limited, Biden reasoned, and the US did more than meet its responsibility to help the Afghan people. The US and its allies provided material and moral support to an army of 300,000. The prudential just war criteria I spelled out above called for an end to what, in Biden's eyes, had turned into a forever war.

Critics, of course, see in Biden's decision a failure to meet America's responsibility. Referring to the late former Secretary of State Colin Powell, they invoke the “Pottery Barn Rule,” the idea of “you break it, you own it.” Some, including two of Biden's top generals, argued at the time that a very limited number of Allied troops would have been able to prevent a collapse of the Afghan security forces (Zurcher 2021). That, they held, would have been a price worth paying. A similar argument was made by the UK government, which made the case to keep a limited NATO presence in order to bolster the morale of the Afghan security forces. The British Catholic weekly The Tablet (2021) also noted that only a very limited number of Allied troops died in the time after the combat mission had ended. Additionally, if successful, a limited presence could have prevented the anticipated mass exodus of Afghans seeking to flee the Taliban. It is worth keeping in mind the possible impact of a wave of mass migration on Afghanistan's neighbors and, one might add, on the political stability of Europe, the destination of dreams of those fleeing the country (see Goldbaum and Akbary 2022).

So where does this leave us? Going back to classical just war reasoning, I argue that it was, in the end, on Biden to take sides in this debate. The issue of the hasty pullout of troops notwithstanding, I tend to agree with the US president. Shortly after the withdrawal decision had been executed, the Catholic German Military Bishop, Franz-Josef Overbeck (as cited in Altmann 2021), argued that one of the key lessons for future military interventions would be to start with thinking about the mission's end. In particular, cultural, religious, social and ethnic aspects should be considered before the start of future humanitarian interventions or attempts at nation-building. I interpret the bishop's remarks as giving renewed emphasis to the criterion of right intention. The prudential criteria of just war, I think, would have cautioned against overly ambitious objectives in Afghanistan. Put differently, five additional years, or ten, of NATO forces in Afghanistan would also not have succeeded in building a sustainable Western-style democracy. As I understand Pope Francis's remarks (as cited in Povoledo 2021) on Afghanistan, this is the assessment of the pope, too. Of course, that does not mean that any humanitarian project is set to fail. However, the specific case of Afghanistan with its history of failed interventions, the infamous “graveyard of empires,” would have called for skepticism. Nobody can credibly accuse the West of not having made an effort to build a functioning Afghan state. To consider only one specific example, let's remember the “surge” in Afghanistan that President Obama ordered at the time. Obama's embrace of the “Coindinistas” had also been a defeat of Vice President Biden, who had advocated a more focused and limited counterterrorism campaign (see Baker 2009).

Some 2300 US troops as well as hundreds of soldiers from many other nations made the ultimate sacrifice in Afghanistan. In addition, more than $2 trillion was spent. The prudential just war criteria ask leaders to constantly question the rationale for going to and being at war. In other words, the Pottery Barn Rule may need to be amended: “If you break it and, then, own it, for how long do you own it?” And for Afghanistan one might add: “For how long should you pretend to be owning it?” Perhaps the killing of Osama bin Laden in 2011, notably in Pakistan, not Afghanistan, could have been a good end point. Potentially, it could have provided some sort of closure a decade after the 9/11 attacks and it could have been a reminder that the West went to Afghanistan to go after al Qaeda, not to do nation-building. In any case, it would have ended the war a decade earlier.

In retrospect, and perhaps it took 20 years to realize it, nation-building in Afghanistan was never likely to succeed. As Commonweal Magazine (2021) put it, the war in Afghanistan in the way it developed was “an unwinnable war.” Of course, that is an easy argument to make with hindsight. However, the effort to build a functioning government never came to fruition. Relatedly, before the Taliban takeover, 40 percent of Afghanistan's GDP came from foreign aid—an unsustainable state of affairs. The role Pakistan played in preventing the US from beating the Taliban also contributed to losing the war. Above all, the Afghanistan mission showed little understanding of the tribal nature of the country, its various forms of Islam and the, relatively speaking, more liberal urban and profoundly conservative and patriarchal rural areas. Malkasian (2021, 454) argues that, based on Islam and their opposition to foreign occupation, “the Taliban stood for what it meant to be Afghan.” In the eyes of the majority of the people, the Afghan government was a tool of the US and, therefore, never managed to generate the legitimacy that would have been needed to defeat the Taliban. If Malkasian's analysis is correct, the war in Afghanistan was unwinnable indeed. Importantly, this is not to say that the soldiers who served in Afghanistan did so in vain. The counterterrorism mission succeeded in the sense that no major terrorist attack post-9/11 originated from Afghanistan. Moreover, the hope is that the 20 years of the Western effort in Afghanistan have planted the seeds of freedom and equality in those who despise the Taliban ideology. The servicemen and women who helped do this have all reason to be proud of their service. However, despite the great theological virtue of hope, the just war tradition also asks us to be realistic and prudent. I think this should be the number one lesson from the war in Afghanistan—a lesson the classical bellum justum can teach us.

Acknowledgments

An earlier version of this article was presented at the Chaplains and Religious Support Leaders Conference: Chaplaincy and NATO Interoperability, Headquarters Allied Rapid Reaction Corps, Imjin Barracks, Innsworth, Gloucestershire, November 1–4, 2021. I am also grateful to the two anonymous reviewers who provided very helpful feedback.

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Christian Nikolaus Braun

Christian Nikolaus Braun is a Radboud Excellence Initiative Fellow at Radboud University's Research Centre for State and Law (SteR). He is also a Visiting Fellow of the Institute of Political Science at the University of Luxembourg. Previously, Christian was a Senior Lecturer in the Defence and International Affairs Department at the Royal Military Academy Sandhurst. In his current research project, he explores contemporary Catholic thinking on war and peace. Christian's research has been published in several peer-reviewed journals, including Global Studies Quarterly, International Relations, International Theory, the Journal of Military Ethics, and the Journal of International Political Theory. His first research monograph, titled Limited Force and the Fight for the Just War Tradition, is forthcoming with Georgetown University Press.

Notes

1 For such a neo-classical reading of just war, see Braun 2023. For an argument that suggests that there are general lessons to be learnt from medieval thought with regard to the international politics of today, see Bain 2017.

2 For an in-depth discussion of Aquinas's thinking on war and peace, see Reichberg 2017.

3 See Braun 2019 for an assessment of the continuing role of retribution in contemporary military conduct.

4 See Johnson 2014 for a succinct account of the change in the understanding of sovereignty.

5 See Cole 1999; Gorman 2010.

6 For a thoughtful discussion of “military prudence” in Aquinas's account of just war, see Reichberg 2017 (chap. 4).

7 See, for example, Allman and Winright 2010; Bellamy 2008; Mileham 2020; Orend 2013 (chaps. 6–7); Stahn, Easterday, and Iverson 2014.

8 Some scholars (e.g. Mollendorf 2008) have argued for a jus ex bello, the justice of ending wars. I prefer to use the language of jus post bellum, as an ever-increasing number of ethical categories can overcomplicate the conversation.

9 See also Patterson 2012a.

10 I am thankful to an anonymous reviewer who pointed me to the distinction between ends and means.

11 See Coll and Entous 2021.

12 For such a third-way argument, see Afzal 2021.

13 Dodge 2021 identifies the war's expansion toward attempting “liberal peacebuilding” as the main reason for the defeat.