The morality of warfare has been in the news recently.
This occurs every so often, usually when the United States launches a dubious military action (like the one against Iran) and someone in the administration (like JD Vance) claims the support of Just War Theory for that action.
In recent years, such claims often have been met by resistance from the most visible Christian cleric in the world, the Roman Catholic pope.
David Gushee
Both Pope Francis and now Pope Leo XIV have criticized wars in general, and U.S.-initiated military actions in particular. Interestingly, both now have directly challenged Just War Theory, which for many centuries served as the Catholic Church’s primary framework for thinking about war.
Pope Francis (in Fratelli Tutti, 2020): “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!”
Pope Leo XIV (in Magnifica Humanitas, 2026): “Without prejudice to the right to self-defense in the strictest sense, it is important to reaffirm that the ‘just war’ theory, which has all too often been used to justify any kind of war, is now outdated. Humanity possesses far more effective and capable tools for promoting human life and resolving conflicts, such as dialogue, diplomacy and forgiveness. The use of force, violence and weapons reflects a relational poverty that always has disastrous consequences for civilian populations.”
7 theses on ethics of war
As a Christian ethicist who has for decades taught courses about the ethics of war and done a bit of writing in this space, I would like to propose the following seven theses for consideration about the Christian ethics of war.
First, most recent claims invoking Just War Theory for military incursions appear both thin and cynical. Every thin and cynical summoning makes the theory itself seem ever less credible. Pope Leo XIV gets at that in his recent statement that Just War Theory “has all too often been used to justify any kind of war.”
“Every thin and cynical summoning makes the theory itself seem ever less credible.”
Second, there is no doubt that Just War Theory was developed in historical circumstances far different from our own. It has been almost 17 centuries since Augustine. The distance makes this theory increasingly seem baroque and any reference to it an anachronism.
The lethality of modern warfare has staggered Christian observers since at least World War I, then again in the nuclear age, and now, the integration of AI into warfare is the latest stunning technological innovation. We are a long way from the fourth century.
Third, Just War Theory is (or was) fundamentally rooted in the legitimacy of a people’s right to defend itself. Apart from potential divine revelation to the contrary, it is hard to resist the claim that persons and peoples have the right to defend themselves when attacked. The principle is so widely accepted that it forms part of the moral logic of criminal law and is explicitly recognized in modern international law.
We have been witnessing one such compelling act of national self-defense — that which is being undertaken by the Ukrainian people — for many years. It is hard to seriously entertain the idea that their national self-defense is immoral or wrong.
Fourth, Just War Theory also can be justified as an expression of love of neighbor. Soldiers defending their homes, families and neighbors from unjust attack, at risk of their own lives, can be viewed as acting in unselfish love. Allies supporting an attacked nation, at some risk or cost to themselves, also can be viewed as acting in solidaristic love of a vulnerable other.
Fifth, but (a) oftentimes the right of national self-defense is invoked to justify aggressive attacks that are framed as preemptive self-defense and (b) the cyclical and often escalatory nature of this supposedly always-merely-defensive violence is ever and ever again visible.
“An eye for an eye ends up making the whole world blind.”
A saying often attributed to Gandhi — “an eye for an eye ends up making the whole world blind” — pointedly articulates this truth. It is not unreasonable to fear humanity will ultimately annihilate itself with its weaponry, with all sides claiming until the bitter end the justice of their cause.
Sixth, I alluded above to “potential divine revelation to the contrary.” Of course, as a Christian, I am referring to the life and teachings of Jesus Christ. His nonviolent practice, refusal to defend himself as he went to the Cross, and teaching of peacemaking, forgiveness and enemy-love are impossible to reconcile straightforwardly with participation in war, even defensive war.
The radicalism of this witness somehow matches and responds to the radicalism of the violence that comes so naturally to human beings and communities. The pacifist position, the absolute rejection of war, will survive within Christianity presumably until Jesus returns because it is the most obvious implication of his overall witness.
Seventh, but so also will survive the felt need to deter, prevent and respond to aggressive attacks on the community in which one lives. Just War Theory sought to integrate these complexities, paradoxes and competing impulses into a grand overarching theory. If we should now decide that Just War Theory is outdated, the issues it once addressed nonetheless remain.
Social Ethos
In recent years I have been using the impressive text “For the Life of the World: Toward a Social Ethos of the Orthodox Church” as a teaching tool in ethics survey courses. This crisp document addresses most major social ethics issues and can be said to speak for at least a significant part of the Eastern Orthodox community.
In its discussion of war, the Social Ethos statement makes the following moves:
- “The violence intentionally perpetrated by rational human agents, especially when organized and prosecuted on a massive scale as war between peoples or nations, is the most terrible manifestation of the reign of sin and death in all things. Nothing is more contrary to God’s will for creatures fashioned in his image and likeness than violence one against another, and nothing more sacrilegious than the organized practice of mass killing.” Summary: War is evil, and sinful, and we oppose it utterly.
- “Every act of violence against another human being is, in truth, violence against a member of one’s own family, and the killing of another human being — even when and where inevitable — is the killing of one’s own brother or sister.” Summary: War is nothing less than fratricide.
- “Peace, for the church, is more than a state of armistice lightly imposed upon a naturally violent world. It is, rather, a real revelation of the still deeper reality of creation as God intends it. … True peace is the very presence of God among us.” Summary: Peace is normative. Peace is the presence of God.
- “And yet the church knows that it cannot foresee every contingency to which persons or peoples must respond at any given moment, and that in a fallen and broken world there are times when there is no perfectly peaceful means of cultivating peace for everyone. While unequivocally condemning violence of any kind, it nevertheless recognizes the tragic necessity of individuals or communities or states using force to defend themselves and others from the immediate threat of violence.” Summary: We unequivocally condemn violence while also recognizing the tragic necessity of defending self and others from unjust attack. Here the central paradox emerges.
- “The Orthodox Church has not historically insisted upon a strictly pacifist response to war, violence and oppression; neither has the church prohibited the faithful from serving in the military or police. … And yet the Orthodox Church has also never developed any kind of ‘Just War Theory’ that seeks in advance, and under a set of abstract principles, to justify and morally endorse a state’s use of violence when a set of general criteria are met. Indeed, it could never refer to war as ‘holy’ or ‘just.’ Instead, the church has merely recognized the inescapably tragic reality that sin sometimes requires a heartbreaking choice between allowing violence to continue or employing force to bring that violence to an end, even though it never ceases to pray for peace, and even though it knows that the use of coercive force is always a morally imperfect response to any situation.” Summary: We never have codified our stance into a Just War Theory. We recognize the “inescapably tragic reality” and “heartbreaking choice(s)” that arise in this broken world, including using violence in self-defense.
More to be said
There is more to be said about the Christian ethics of war — always more to be said. Focusing the church’s attention on practical, effective “just peacemaking” strategies was my dear teacher Glen Stassen’s solution. He recognized the debate between pacifism and just war, never-violence vs. sometimes-violence, never would be resolved.
But meanwhile both groups ought to be able to get behind effective practices for making peace. If Glen were still with us, I am quite certain he would be making or elevating proposals for a permanent negotiated settlement of the U.S.-Iran-Lebanon-Israel situation. In this he would track closely with Pope Leo’s recent statement.
Just peacemaking, certainly, always, yes. But still, there is no resolution to the paradoxes in Christian thinking about war.
War is unspeakably tragic, an awful desecration of human life; and people have the right to defend themselves when attacked; and they will almost certainly do so if they have the means; and their efforts to do so never can be called, simply, “just” and they often are very far from just; and Jesus taught and embodied a better way; and peace is the norm; and peace is the very presence of God.
These are the realities, tragedies and paradoxes that will remain with us until the end of human history.
David P. Gushee serves as Distinguished University Professor of Christian Ethics at Mercer University, chair in Christian social ethics at Vrije Universiteit Amsterdam and senior research fellow at International Baptist Theological Study Centre. He is past president of the American Academy of Religion and Society of Christian Ethics. He also is author of 30 books, including Righteous Gentiles of the Holocaust; Kingdom Ethics; Defending Democracy from Its Christian Enemies; Changing Our Mind; and The Moral Teachings of Jesus.