It Is Far More Complex Than What the Pope Claims
With the U.S. war in Iran, debates about just war and the ethics of warfare have unsurprisingly reemerged. The threat of nuclear weapons and the Vietnam War spurred the initial revival of just war thinking in the 1960s. At the height of nuclear tensions between the U.S. and the Soviet Union in the 1980s, there was another flurry. Both Iraq wars had a similar effect, as did the slow-burning Global War on Terrorism and its correlative depredations. The targeted killings of Anwar al-Awlaki and Osama bin Laden and the massive expansion of drone warfare as the tip of the spear in the War on Terror elicited another round of discussions in Obama’s second term.
The recent interest in just war was to be expected, especially in the second Trump administration, where flouting international law and norms have become core to the president’s messaging on foreign policy and use of force. In this light, Pope Leo XIV’s denunciation of the Iran War is standard fare from recent Roman pontiffs. From at least John XXIII’s seminal 1963 encyclical, Pacem in Terris, papal teaching on war has taken a decidedly liberal internationalist turn, with a highly restricted view of when force is permissible.
The modern papacy does not see war as a legitimate tool of statecraft. Papal defenders will bristle at this claim, retorting that Catholic teaching clearly provides grounds for the just use of force, which is true, but what it provides in theory it takes away in practice. Since John XXIII, no pontiff has found a war that meets its exacting standards. So when Leo stated in a recent X post that “God does not bless any conflict” and that a “disciple of Christ” is “never on the side of those who once wielded the sword and today drop bombs,” he was keeping with the trajectory of contemporary papal pronouncements. These words were clearly meant for the Trump administration and Catholics and Christians who support the Iran War.
In response to Secretary of War Hegseth’s prayer delivered at a Pentagon worship service, during which he prayed for violent force against Iranian enemies, Leo rebuked the secretary in his Easter homily, stating that “Jesus does not listen to the prayers of those who wage war” and have “‘hands full of blood.’” The straightforward reading of this pronouncement forecloses the possibility of wars being fought for just reasons.
Following closely on the heels of Leo’s X post, 60 Minutes aired its interview with senior American Catholic clerics who publicly declared that the Iran War is unjust according to Catholic just war teaching. It is hard not to see some coordination with the timing of these comments.
Enter the Pope’s defenders, who explained how what the Pope really meant was something else. Perhaps, but for those of us without a Ph.D. in papal rhetoric and who are unable to discover the secret meaning in every papal statement, Leo comes across as a pacifist, plain and simple.
Liberals and Catholics have rallied to the Pope’s defense in the aftermath of Trump’s criticisms, claiming the president’s counterpunch was inappropriate, crossing the line of papal decorum. Apparently, Americans are supposed to welcome the moral pronouncements of the Roman pontiff on American policy because such toleration has been extended to previous popes. Whatever one makes of the style of Trump’s delivery, when the pope decides to play pundit and weigh in on American policy, especially in the sweeping and absolute fashion that he has, his statements should not be treated as having some special authority, because for the vast majority of Americans, they do not. His criticisms rise and fall based on their merits.
Through the rhetorical bombast, however, there are serious questions at play. The invocation of “just war theory” by critics of the Iran War masks deep divisions and debates within the just war tradition itself, a very old and complex intellectual tradition whose origins date back to the 4th-century bishop Ambrose of Milan. There are fundamental disagreements among just war proponents. And there always have been. We need to be clear about that so that our disagreements are productive and honest. Merely calling the Iran War unjust does not make it so. The claims of clerics and popes need to be tested and examined on the basis of this tradition.
Tradition, Not Theory
When the Pope makes sweeping claims about the “Christian” view of war without any qualification, as if Just War were one monolithic entity, he is speaking recklessly. The contemporary differences among Christians on just war break down roughly into two camps, one more permissive and the other more restrictive, with a third being pacifism, but since that group rejects war as a moral enterprise completely, we can set them aside.
Just war ethics slowly developed across centuries, and have been evolving ever since. It is not one single coherent body of teaching that descended from heaven. When Leo, senior clerics, or Catholic laity refer to the 1,000-year-old just war tradition, the appropriate response should be, “Whose tradition? Which tradition?”
Bishop Mark Massa, defending the Pope’s statements on war after criticism from Catholic Vice President JD Vance, stated, “For over a thousand years, the Catholic Church has taught just war theory, and it is that long tradition the Holy Father carefully references in his comments on war.” While true to an extent, Massa presents just war as a static body of doctrine—“just war theory.” There is not one single doctrine, however, but a multiplicity of schools, lawyers, theologians, and clergy who have written on the topic, and they disagree quite fiercely, Catholic, Protestant, or otherwise.
Take, for example, one of the most hotly debated issues in the just war tradition: the Crusades. Catholics debated the issue for hundreds of years for a reason: the complexities of the crusades in legal, moral, and theological terms are immense. Crusading was broadly accepted as a legitimate form of warfare by leading figures of the day. Centuries later, the Catholic clergy have denounced it, but they are at odds with their forebears.
We find the first invocations of the just war tradition in the writings of Ambrose of Milan and his most influential pupil, Augustine of Hippo. Though Augustine himself never wrote a treatise on war, his occasional comments were collected and collated into florilegia (collected quotations from various figures on a topic), which were then passed down to clerics, lawyers, and theologians who wrote and debated the topic. There is a core to the tradition, but it remains flexible and reactive to the changing conditions of politics, authority, and warfare. Technological development also induces reassessments of discriminate use of force.
The vast majority of writing on the ethics of warfare in the High Middle Ages—which is when the tradition comes together as an authoritative body of literature—concerned what we refer to as ius ad bellum—the justice of going to war. The theologians and writers of that time were trying to give a compelling and coherent answer to the question of whether it is sinful to fight in a war and under what conditions it is just. The two most influential figures of this period, Gratian and Thomas Aquinas, argued that fighting in a war is not necessarily sinful and can be just as long as it is fought under certain conditions. Here, Aquinas’s influential formulation of the three core principles of ius ad bellum is stated as right authority, just cause, and right intention. Augustine alludes to all these criteria in his own writings, as does Gratian, but neither states them in the clear and succinct manner of Aquinas.
The initial developments in ius in bello had more to do with the norms of chivalry than any sort of hard-and-fast principles about combatants or noncombatants. The honor of the knight and customs among the warrior class were more definitive. That is not how we think about ius in bello today. International law and some just war proponents treat the ius in bello criteria as rooted in human rights, an idea that would have been completely foreign to Augustine and Aquinas.
All this to say, the just war tradition is not a theory as we think about theory. Christians drew from the Bible that engaging in warfare could sometimes be considered a just act, looking at King David or Samson. They were also keenly aware of the biblical command to love one’s neighbor. Just war ethics arose out of practical necessity and biblical imperative, not theoretical formulation and refinement. It developed across history in different contexts. It is a thoroughly practical discipline, in that its goal is right action, not theoretical elegance.
This brings us back to the debates that continue to rage today. The Catholic position on just war is one of many, and not the dominant one. Among academics, the work of Michael Walzer has shaped the discipline since the 1970s. His magisterial Just and Unjust Wars is the most influential contemporary treatment of just war ethics. A school called Revisionism, which finds its origins in the work of philosopher Jeff McMahan, has been most influential in recent academic scholarship. Among Christians, especially conservative Protestants, evangelicals, and some Catholics, Christian Realism and classic just war ethics influenced by the work of James Turner Johnson and Jean Bethke Elshtain have held sway. So when Pope Leo invokes “just war theory” as a single entity, he is referencing something that does not exist.
Presumption Against War
The differences between Protestants and Catholics trace in part to very old and deep disagreements over politics. Protestants have always had a strong attachment to the nation-state and a more realistic view of international politics and the use of force. On matters of war, especially in the aftermath of World War II, the divides have become clearer. Catholics and Europeans as a whole, who experienced the worst ravages of the war, understandably seek to prevent war at all costs as a matter of policy. The U.S. retains a more positive view of war as a tool of statecraft than one finds in the Anglosphere.
This becomes clear on basic questions about the purpose of just war ethics. The famous and influential National Conference of Catholic Bishops’ pastoral letter on just war from 1983, The Challenge of Peace, grounded its argument in a “presumption against war.” This means that the focus of the just war tradition becomes fundamentally about preventing the recourse to armed force. Force is a last resort and should be avoided in favor of non-coercive alternatives. This presumption is rooted in a conviction that war is evil, but a necessary evil. In one sense, this is clearly the case. The death and destruction that accompany war are truly tragic and lamentable.
The U.S. bishops wrote the letter in the context of the possibility of nuclear war breaking out between the U.S. and the USSR. Given that background, one can sympathize with their desire to restrain war at all costs. Any nuclear exchange between the U.S. and the USSR could have spelled the annihilation of the entire planet. And yet, that does not justify their framing war as an occasionally permissible evil.
The Catholic bishops’ presumption against war is excessively negative and lapses into a view of war that finds no positive purpose; hence, Pope Francis’s consistent claim that war is “always a defeat for humanity.” In the words of just war scholar James Turner Johnson, “[O]nce one has begun by describing war as always something negative, it is conceptually impossible to represent it as a way to peace.”
While the presumption against war position claims the moral high ground, in practice, it makes resort to lethal force all but morally impossible. There has not been a single war in the past 60 years that the popes have deemed just, including wars that garnered near universal support like the 1991 Gulf War. The result is what scholars have called “practical pacifism.” Theoretically, war can be just, but in practice, the right conditions are never present, and, hence, popes, including the current pope, are pacifists for all intents and purposes.
The presumption against war position promulgated by Leo and most modern popes is a departure from the classic just war position articulated in the Middle Ages and the early modern period. War, while tragic, was viewed as a tool of statecraft that could be morally appropriate under certain conditions. War was seen as a tool to address injustice, not an evil that must be avoided except in rare instances.
The use of armed force has brought immeasurable good through protecting the innocent and punishing wrongdoers. It has brought peace and established order. Clearly, there have been mistakes and failures in the recent past, but abuse does not negate proper use.
An even bigger problem with viewing war as a necessary evil is that it invites us to do evil that good may come, which is deeply antithetical to the moral integrity of our nation. War may cause death and destruction, but the whole point of just war ethics is to use military force for moral purposes. The classic tradition believed war could be waged morally and that, despite its tragic quality, it was a good and noble undertaking when waged in a just manner. If war is just, then the use of force is good, not evil.
The perverse result of the good coming from evil approach is that to keep our hands and consciences clean, we offload the evil work to the members of our military, who are told they are essentially butchers doing the dirty work the common American refuses to do. It is wicked. Many of our servicemembers have accepted the view that what they do is evil, even if necessary, and the psychological effects are devastating.
Power and Authority
A second point of tension has to do with the role of political authority and power. The revival of just war thinking in the U.S. happened in the 1960s through the writings of Princeton professor Paul Ramsey, a Southerner and a Methodist who sought to recapture just war by recovering the Augustinian idea that war is rooted in love for the neighbor. The pressing issue of the 1960s that motivated Ramsey to write was nuclear weapons, as it would be through the 1980s until the fall of the Soviet Union.
In contrast to Catholics, who took a much more restricted view on the acceptable use of force, especially in the aftermath of the destruction of Europe and the looming Soviet threat, Protestants like Ramsey and his predecessor, Reinhold Niebuhr, accepted a more realistic appraisal of the nature of politics and, thus, war. Although Ramsey diverged from Niebuhr in important ways, both accepted that power exercised responsibly was a central feature of politics.
Ramsey’s classic The Just War begins with a programmatic essay, “On the Uses of Power,” in which he argued that the use of force is a political tool that should be exercised with care, but it is not evil by nature. He writes,
The use of power, and possibly the use of force, is of the esse of politics. By this I mean it belongs to politics’ very act of being politics. You never have politics without the use of power, possibly armed force. At the same time the use of power, and possibly the use of force, is inseparable from the bene esse of politics, inseparable from the well being of politics, inseparable from the human pursuit of the national or international common good by political means. You never have good politics without the use of power, possibly armed force.
Ramsey prefaced his book with this essay to clarify two things: power is essential to politics, and having an armed force is an intrinsic part of political power.
American liberals in the ‘60s came to view power as a problem to be overcome, a relic of pre-World War II. The liberals of Ramsey’s day had visions of a United Nations that could solve all the world’s problems. A new dawn was rising in which politics itself would transform from geopolitical contests into world government and rule by reason. Mainline Protestants, especially their leaders, and Catholics moved in this direction over the following decades, though Catholics retained the just war tradition, while mainline Protestants embraced an essentially anti-war position.
Ramsey represented the long-held conviction in Protestant America that politics and armed force were inseparable and connected to a longer tradition of statecraft that charged political leaders with the responsible use of force in the service of the nation. Power, rather than being evil or something to stigmatize, was a necessary ingredient to any Protestant account of politics.
The more essential disagreement, however, between Catholics and Protestants was over the role of political authority with respect to the church. Even in a post-Vatican II world, the Catholic church, and popes in particular, claim the right and duty to speak to states on issues of morality. Ramsey, again, channeling the older Protestant ethos on this question, argued that the church is not charged with making moral judgments about political issues or instructing politicians on the right policy. “In politics,” he writes, “the church is only a theoretician.” Drawing upon the classic Protestant two-kingdoms doctrine, Ramsey believed the duty of the magistrate is an exalted one, and that the church’s duty with respect to politics is not to instruct the magistrate what to do but to clarify the church’s teachings on politics on any given topic. It is decidedly not to shape policy.
Here, the Protestant and Catholic divide is pronounced. Catholics believe the church possesses the authority to instruct the nations. For Protestants, individual Christians should serve as magistrates and guide the state according to Christian precepts, but the church itself has no such political authority. Though Ramsey never used the phrase, he was articulating a consistent view of the “spirituality of the church.” The church has a duty to instruct Christians on Christian ethics and political doctrines, but it possesses no authority to speak to the state directly. If Protestant pastors decide to address the magistrate, they do so not to shape or influence policy but as an aid to the magistrate in making an informed decision. Pastors may develop their own views on any number of political issues, but they do so as citizens of a political community—not in virtue of any special authority they possess as pastors.
This strong view of the magistrate coincides with the classic just war conviction that the rightful exercise of arms for any political community starts with right authority, not just cause. Political authority alone is responsible for the protection of the community and, likewise, is accountable to God for the exercise of his office. The magistrate must decide what constitutes a just cause, not the public, pundits, or clerics. The church should instruct those in their congregations who serve in politics on the basic concepts from Christian tradition, and perhaps even present trains of thought, or paradigmatic cases, to guide deliberations and decisions. What the church must not do is play the role of pundit or critic or, even worse, politician. It does not possess that authority and should not attempt to usurp it.
Returning to Pope Leo’s recent pronouncements on the Iran War, the Protestant rejoinder is that the Pope does not possess the authority to instruct the president of the United States, or any world leader for that matter, on what they should do. It is simply not given to the church to play that role.
A related point, and one that has been painfully on display in Leo’s comments and those of Catholic leadership, is that they also do not possess the competence to render these judgments. Invoking an understanding of just war’s complex history does not qualify one to make a simple judgment about the justice of a particular conflict. Did Leo see all the intelligence? Does he have a comprehensive understanding of the nature of Iran’s threat to the region? Has he spent time talking with military leaders, gaming out various scenarios? The answer is clearly no. And it is clear that when Leo or other Catholic church leaders pontificate on complex matters of war and international politics, they more often than not lack the requisite understanding of these issues to render a competent and responsible judgment. Merely making the most moralistic judgment does not make it the most moral. Such a judgment must take a host of contingent variables into account, which comes with understanding the whole of the conflict and the limited choices available.
These differences between Protestants and Catholics in terms of just war, and in politics in general, are significant, and it is not likely they will be bridged. For the benefit of mutual understanding, we should try our best to be clear about how and why we see things differently. If we intend to work together for the good of the United States, it is imperative not only that we explain our differences but also that we have a certain amount of respect for complex histories that make our churches come to very different views on political matters.
