U.S. Bishops Warn of A.I. in Warfare Echoing the Call of Pope Leo XIV for World Leaders to Seek Peace

Magnifica Humanitas and Warfare in the Age of AI
“No algorithm can make war morally acceptable. AI does not remove the intrinsic inhumanity of conflict”

– Pope Leo XIV, Magnifica Humanitas, no. 198

USCCB - Moral Judgment in War: An Exclusively Human Domain

Despite our continuous cries for peace, war is too often a “shameful” reality in our world. In our very broken world, the reality of war forces us to confront the evolving race for munitions. Pope Leo notes in Magnifica Humanitas that the “new arms race” is made possible by our current "relational poverty" that leads to the use of force and by economic and political interests opposed to building a culture of authentic peace (nos. 192-293).

In the age of artificial intelligence, the Church’s teaching on human dignity, pursuit of justice, and comprehensive social doctrine offers a path forward that transcends the logic of zero-sum escalation. Instead, the world must come to embrace the "far more effective and capable tools for promoting human life and resolving conflicts, such as dialogue, diplomacy and forgiveness" (no. 192).

Pope Leo offers a new framework for an approach to how we must limit the use of technology in war. He insists that the world can and must maintain limits on the use of force in the age of AI. He writes: There must always be accountability to a human person with a clear chain of responsibility.
Lethal force cannot be delegated to automated processes and must remain with self-aware, responsible human control.
We must work as a collective, global community to build a shared framework that curbs the arms race and preserves civilians and infrastructures. (no. 200)

In a particular example, the rise of lethal autonomous weapons systems are a grave development of military technology. In a particular example, the rise of lethal autonomous weapons systems is a grave development of military technology. These systems use AI to identify, locate, and kill people or destroy infrastructure targets without human operational intervention. Unlike unmanned drones—which are remotely controlled by human operators—autonomous “killer bots” are preprogrammed with algorithms that search according to target profiles, and can, theoretically, make battlefield decisions independently from human control.

The Holy See has consistently recognized the inherent problem with taking life and death decisions away from the moral agency of human beings. Pope Leo says, “Moral judgment cannot be reduced to calculation, for it involves conscience, personal responsibility and the recognition of the other as a person. Therefore, it is not permissible to entrust lethal or otherwise irreversible decisions to artificial systems” (no. 198).

Judgments over life and death, the gravest of human challenges, must remain bound to our living consciences: “The heavens belong to the Lord, but he has given the earth to the children of Adam” (Psalm 115:16). In the age of artificial intelligence, by removing human agency, our ability to wage war has become more inhumane in its most fundamental sense.

Reducing War’s Threshold: Conflict Multiplication and Proliferation

While minimizing the risk to military personnel is a laudable goal, employing technologies that completely remove human agency can create the illusion of lessening the cost of war, and thus reducing the conflict threshold. Pope Leo prophetically teaches, “Any technology that facilitates attacks without seeing the face of human beings lowers the moral threshold of conflict” (no. 198). The illusion of making war politically and economically less costly will make decisions to go to war easier. “AI does not remove the intrinsic inhumanity of conflict; indeed it can only bring about conflict more quickly and render it more impersonal, lowering the threshold for resorting to violence, transforming defense into threat prediction and thus reducing victims to data.”

While the Church works and prays ardently for the day when all leaders will seek the pathway of peace, built upon mutual respect and engagement, we must at the same time, speak clearly about the immense harm and loss of human life these weapons present. All people, soldiers, civilians, and leaders alike, are harmed by a reality in which our actions are inherently less human, less connected to the embodiment of our human dignity that God himself “knit” together.

Find more resources for International Justice and Peace or Pope Leo’s first encyclical on our webpages.

Magnifica Humanitas War Backgrounder.pdf

USCCB Release