Pope Leo XIV Calls for AI Slowdown and Autonomous Weapons Controls in First Encyclical

Pope Leo XIV released his first encyclical on Monday, urging governments worldwide to slow the development of artificial intelligence and impose tighter oversight on autonomous weapons systems, in a nearly 43,000-word document titled "Magnifica Humanitas."

The text — one of the highest forms of papal teaching, addressed to the Church's 1.4 billion members — argues that policymakers must act with "clarity to establish adequate regulatory tools capable of upholding justice and curbing the distorting effects of technological power."

"What is needed is a more active political involvement that is capable of slowing things down when everything is accelerating," Leo wrote in the document, calling for "robust legal frameworks, independent oversight, informed users and a political system that does not abdicate its responsibility."

Leo, the first American-born pope, expressed particular alarm at autonomous weapons, saying at a Vatican event Monday that some such systems had advanced "practically beyond any human reach to govern them." He declared it "not permissible" to entrust AI systems with lethal decisions, and said any AI application in warfare "must be subject to the most rigorous ethical constraints."

The encyclical has been in development for nearly the full year-plus since Leo's election, and its release lands amid ongoing international debate over AI governance. The Vatican event was attended by Chris Olah, a co-founder of Anthropic, the company behind the Claude AI tools.

Olah thanked Leo for taking up the subject and acknowledged the commercial pressures bearing on firms like his. "Every frontier AI lab, including Anthropic, operates inside a set of incentives and constraints that can sometimes conflict with doing the right thing," Olah said at the event.

On the question of data ownership, Leo called for AI data not to be held solely by private entities, and urged policymakers to protect workers' rights and shield children from potential harms. He also called for reduced competitive intensity among AI companies.

The document drew a direct line between AI's rise and broader questions of economic justice. Leo invoked his predecessor Leo XIII, whose 1891 encyclical addressed labor conditions during the Industrial Revolution, and applied a similar framework to the present moment — describing "new forms of slavery" endured by workers who tend AI systems, as well as those who manufacture the hardware on which such systems run.

"In some regions of the world, children and adolescents work in dangerous conditions, crushing the materials from which rare earth elements are extracted," Leo wrote. "The bodies of these people are scarred, injured and worn down so that computational flow may continue uninterruptedly."

The encyclical also broke sharply with longstanding Church doctrine on armed conflict. Leo declared the "just war" theory — used by the Catholic Church since at least the fifth century — "now outdated," adding that "the use of force, violence and weapons reflects a relational poverty that always has disastrous consequences for civilian populations." That doctrine has recently been invoked by Trump administration officials, including Vice President JD Vance, a Catholic, to justify the administration's posture on the Iran war.

Leo also warned that leaders might pursue military action as a domestic distraction. "We cannot rule out the possibility that some leaders may consider armed conflict as an effective way of diverting attention from domestic problems and a cynical tool for managing difficulties," he stated.

Separately, the document included an apology on behalf of the Church for its delayed condemnation of transatlantic slavery. "The Catholic Church did not forcefully condemn transatlantic slavery until the 19th century," Leo acknowledged, calling it "a wound in Christian memory" and adding, "For this, in the name of the Church, I sincerely ask for pardon."

The encyclical arrives as the White House itself is navigating internal disagreements over AI policy — underscoring that regulatory uncertainty around the technology extends well beyond any single institution. Whether the pope's appeal translates into legislative action in any major jurisdiction remains to be seen, though the document's scope and timing ensure it will feature prominently in ongoing debates over who bears responsibility for governing AI's trajectory.

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