America asked a group of leading Catholic scholars to weigh in on the moral duties just war theory requires of the United States as a cease-fire with Iran is holding in the second month of the conflict. They were asked:
Now that the U.S. is engaged in an ongoing conflict with Iran, what duties does it have toward Iran, the Middle East and the international order according to just war theory?
What obligations does just war theory impose once damage has already been done? Does a violation of just war theory before or during conflict affect duties going forward; if so, how?
Their responses have been edited for length and clarity.
Daniel Philpott, professor of political science at the University of Notre Dame
St. Augustine and St. Thomas Aquinas taught that the goal of a just war is a just peace. As both thinkers as well as recent popes have made clear, a just peace is more than a negative peace, which is an absence of hot war, but is rather a positive peace, which includes the presence of justice.
This is important for the current U.S. war in Iran. Apart from the dubious causes for which the United States initiated the war, the nation has a duty even now to leave behind stability, peace and a modicum of order. A just peace is more than a military victory, which in itself is not easy to define in the present conflict.
To simply lob thousands of missiles into Iran and then turn around and leave is not seeking a just peace. Certainly, free and lawful waterways in the Strait of Hormuz are a duty to the entire community of nations, which depend on these passageways for their livelihood. Should Iran be left in a civil war, that is not a just peace. Leaving civilians in danger of starvation or being without medical supplies is not a just peace, either. In short, the Trump administration has a duty to leave behind a cessation of armed conflict, civilian suffering and lawless interference in commerce.
Maryann Cusimano Love, associate professor of international relations and chair of the Politics Department at the Catholic University of America
The Catholic teaching on just war and just peace is extremely practical. They are often portrayed as if they are somehow idealistic, but the narrow criteria for just war are very realistic. The Catholic Church is the world’s largest denomination, operating in the world’s oldest sovereign state through the oldest diplomatic core, so the church has a lot of practical experience in peace building and with failed wars. Just war theory suggests things that actually work.
Just war tradition tells you how to limit war but does not give you many specifics on how to build peace. It tells you that it is your obligation and that the use of force should be a last resort, but it does not really say much about what those first resorts are.
The just peace principles and practices are implied by just war tradition, but they are not really fleshed out. The principles and practices of just peace give you more of a roadmap of how to put the pieces back together when conflicts have taken place that were very unjust. It tells you that you have to work to expand participation and include the people on the ground who are most impacted by violence. It also requires addressing the environmental damage done from war.
It tells you that you need to restore not just roads, bridges and infrastructure destroyed by war, but also the hearts and minds of those suffering from the trauma of war. It tells you that you have to rebuild the relationship with the people that you are engaged in conflict with.
And that’s sometimes the hardest: to engage in dialogue and envision a future that includes your adversary. It requires engaging in reconciliation, which begins by just telling the truth about what’s happened.
Laurie Johnston, professor of theology and religious studies at Emmanuel College
Christians are called to love our neighbors and love our enemies. Just war theory is a guide for how to deal with situations in which those two commandments conflict: When an enemy is attacking, love of neighbor may require defending the neighbor. But love of the enemy is still required—which is why just war theory puts strict limits on what kinds of defense are morally acceptable. Regardless of why or how a war was begun, the duty to love still holds, and this means there is a moral obligation to seek the good of everyone involved. The harm that has been done by embarking on this unjust war makes it all the more urgent for the United States to immediately end the hostilities and make a genuine effort at repair and reparation.
Father Gerald Murray, canon lawyer and pastor of St. Joseph’s Church in New York, N.Y.
Elsewhere Father Murray has made the case that the conflict in Iran is justified on the basis of just war theory.
The United States and Israel must wage war according to moral and ethical standards that are set forth, for instance, in the Geneva Conventions; these include not targeting civilians, not mistreating or killing prisoners, not attacking civilian sites protected by international humanitarian law unless they are being used by the enemy to attack us, and attempting as much as possible to limit collateral damage. We should also assist our allies who have come under attack by using our military to protect those allies.
The damage done to Iran and to Lebanon by the United States and Israel is the direct result of a legitimate military response to the hostile actions of the Iranian regime and Hezbollah. They bear responsibility for this damage. It is in the interest of the United States and Israel, once the threats are eliminated, to assist those nations to rebuild and to establish friendly relations with the United States and Israel. If war crimes were committed by any party to this conflict, then those responsible for those crimes should be brought to justice.
Joseph E. Capizzi, dean and professor of moral theology at the Catholic University of America
The just war ethic is a political ethic. That means that it recognizes the use of force in the service of legitimate political goods and places “right” or “just intention” at its center. Every use of force has a goal or purpose in mind, like “regime change” or “defense against aggression.” But as a political ethic, just war theory looks to a longer-term political horizon than merely the waging of war.
Once the force of war is being employed, the horizon of politics shifts and must continue to be served by ongoing political engagement. We see this already in the negotiations the Trump administration is carrying out with Iranian political representatives.
Our duties to ourselves, our government’s duties to our nation and our duties to our partner in these negotiations are shaped by the conflict. Presumably, Iran can and will ask, for instance, for some recognition of our responsibility for the deaths of schoolchildren. They may also ask for some financial assistance in rebuilding after the bombing. We will also have demands based on our interests: about their nuclear program, about ceasing or diminishing their support for terror, and so on.
The genius of the just war approach is its recognition of the longitudinal nature of politics and the role the moral use of force plays in politics. Iran is not merely “an enemy.” It is a partner in the establishment of a more just and stable political order. That is proven by the move from force to negotiation. Both sides need politics to constrain war from devastating the possibility of post-war peace that allows each party to serve its own interests and the interests of the international community. This couldn’t be more clear than the global need of a postwar political solution allowing the free movement of goods through the Strait of Hormuz.
Eli S. McCarthy, adjunct lecturer in the Program on Justice and Peace Studies at Georgetown University
As a number of Catholics have argued, the war is unjust, and thus it seems at this point soldiers are called by moral integrity not to cooperate in the war. This can be done in numerous ways, such as slow-walking orders, refusing specific orders or otherwise refusing to participate in the war. Unfortunately, “just war” reasoning doesn’t directly instruct such actions, so we need to appeal to other moral reasoning.
Part of the Catholic moral tradition is just peace reasoning. This provides more robust guidance and practical norms for breaking cycles of violence once they begin. Such norms include nonviolent direct action, which would provide a more robust moral warrant for soldiers refusing to cooperate. Other norms include acknowledging responsibility for harm, re-humanizing language and narratives, independent initiatives to build trust, and diplomacy rooted in human needs. This style of moral reasoning also provides norms for engaging in conflict constructively and building sustainable peace. Here is a sample just peace analysis for the war with Iran.
One risk with centering “just war” reasoning right now is that the focus can become tactical issues—like protecting civilians, using proportional violent force or avoiding war crimes—more than stopping the war. Thus, the war may be more likely to continue. Notably, Pope Leo XIV is not using this style. Instead, he clearly advocates to “reject war,” “lay down weapons,” and build peace through dialogue and cultivating trust.
William O’Neill, S.J., professor emeritus of social ethics at the Jesuit School of Theology at Santa Clara University
The just war tradition invoked by Pope Leo addresses two fundamental questions: Can a just war be waged, and can it be waged justly? In his letter to Boniface, St. Augustine wrote, “War should be waged only as a necessity and waged only that through it God may deliver us from that necessity and preserve us in peace.” War was justified only for the protection of the innocent, not for self-defense. And while St. Thomas Aquinas permitted individual self-defense, war could be justified only for the common good.
Later developments in the jus ad bellum tradition led to specifying criteria of just cause, right intention, legitimate authority, reasonable hope of success, last reasonable resort and proportionality. But a war will be justified only if it is also waged justly: The jus in bello criteria require that strategy and tactics be discriminate (honoring non-combatant immunity) and proportionate (the good envisioned must outweigh the harm foreseen). We cannot destroy the village to save it.
As Leo reminded us, Mr. Trump’s recent genocidal threats belie any possible justification of the war. Indeed, we are now no longer threatening a brutal jihadist regime, but rather the very people we claimed to protect. No genocidal cause can be just and no intention right that envisions the destruction of the Iranian civilization.
And Secretary of Defense Pete Hegseth’s dismissals of international humanitarian law and rules of engagement, moreover, clearly violate the jus in bello norms of discrimination and proportionality. If such dismissal led to the deaths of schoolchildren, Mr. Hegseth could be guilty of a war crime.
In Catholic teaching, a just war can never be waged merely for the sake of self-defense or national security. We must always consider the common good of the most vulnerable—the children, the million forcibly displaced Lebanese, the millions more threatened by acute food insecurity as a result of the war.
Just so, the violation of the common good and the just war norms it entails generates both immediate and longer-term duties: We must immediately and unequivocally renounce any genocidal aims, recognize international humanitarian law and the legitimacy of selective conscientious objection for military personnel, pursue negotiations in good faith, and do all possible to secure a lasting cease-fire.
This does not mean justifying the jihadist regime; they too have betrayed the common good of their people and the region. But even now, we must incrementally “seek the things that make for peace” (Romans 14:19). Above all, we bear obligations of restitution and reparation to the innocent victims so often assimilated to the category of “collateral damage.” For finally, it is not only their humanity we risk betraying; it is our own.
Tobias Winright, professor of moral theology at St. Patrick’s Pontifical University
One of the criteria of just war theory, going back to St. Augustine, is right intent, which entailed that a just war should aim at establishing a just peace, what he called a tranquillitas ordinis. Augustine expected just warriors to be peacemakers, not only establishing a just peace for the nation fighting a just war but also a just peace for the unjust aggressor that is defeated, in order to, as Augustine put it, “lead them back to the advantages of peace,” as well.
To foster this right intent, strict adherence to the other principles of just war theory is crucial. For example, last resort is not a one-off criterion to be simply ticked off on a checklist, but there should be ongoing possibilities for cease-fires and diplomatic negotiations to make sure that further lethal force is truly only the last, or further, resort. In addition, respect for the principle of noncombatant immunity helps to avoid future blowback by trying to avoid or minimize civilian casualties.
As the U.S. bishops noted in their 1983 peace pastoral, “The Challenge of Peace,” no nation should act as if it has “absolute justice” on its side. For the bishops, attention to “comparative justice” should help us to avoid “a crusade mentality” and help us “to restrain the use of force even in a ‘justified’ conflict.”
The principles and practices of post-war justice are meant to follow through with the jus ad bellum criterion of right intent to establish a just peace. Post-war justice offers a framework for not only ending the war, but for peacebuilding that promotes a just and lasting, or sustainable, peace. However, there is no one-size-fits-all formula. It may include regime change from a fascist dictatorship (e.g., Nazi Germany) to a democracy, but criteria such as probability of success still must be taken into consideration.
Another example that Mark Allman and I address in our book, After the Smoke Clears: The Just War Tradition and Post War Justice, is the obligation to clean up the environment from weapons such as cluster munitions (which Iran has used in the present war) and depleted uranium shells. Another duty is to provide care for the military personnel who have participated in combat and suffered physical, mental and moral injuries.
Gerard F. Powers, director of Catholic Peacebuilding Studies at the University of Notre Dame
This is an unjust war, so the Trump administration has a duty to engage in serious, sustained good faith negotiations to end the war and help compensate for the harm done, especially to civilians.
It is an unjust war for many reasons, notably that it is a preventive war to stop a gathering or potential danger—the possibility that Iran could develop a nuclear arsenal—not a response to aggression that is lasting, grave and certain, as required by the Catechism. As Cardinal Ratzinger said in September 2002, “The concept of ‘preventive war’ does not appear in the Catechism.” Resorting to preventive war should not be the means of stopping possible nuclear proliferation.
Finally, President Trump and other senior administration officials have repeatedly indicated that they are not constrained by the jus in bello norms governing the just conduct of war; the latest indication of that is Mr. Trump’s refusal to walk back his threat to attack purely civilian infrastructure and even end Iranian civilization, which would constitute genocide.
Another is the dismissal of most of those in the Pentagon responsible for ensuring that targeting is consistent with the laws of war. Iran has also violated jus in bello norms by targeting civilians and civilian infrastructure.
Going forward, the Trump administration has a responsibility to unequivocally reaffirm the U.S. commitment to international law and norms governing the use of military force. That entails, among other things, that it refrain from “might makes right,” holy war and Christian nationalist justifications for the war and stop indiscriminate and disproportionate use and threats of use of force. It also entails serious, sustained, good faith negotiations to end the war.
Finally, Catholic teaching does not have well-developed jus post bellum norms that govern one’s responsibilities after a war is over, but scholars who have addressed the issue agree that those most responsible for an unjust war should be held accountable and pay reparations/compensation.
The most realistic way to hold the Trump administration and its congressional supporters accountable is through the ballot box.
Reparations could take various forms, including creating a fund for reconstruction of civilian infrastructure that would be controlled by an accountable international body. The United States could also reduce tariffs and restore the development aid that has been cut so drastically over the past year in order to compensate for the harm this war has caused so many around the world, especially the poor.
Editor’s Note: This article has been amended to include a resource link.
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