Pope Leo XIV addresses world leaders to mark first anniversary
In his first anniversary address, Pope Leo asked that God inspire world leaders to calm tensions in the world.
VATICAN CITY, May 25 (Reuters) – Pope Leo called on governments to slow down and tightly regulate the development of AI systems in his first major document released on Monday, warning that they risk spreading misinformation, favoring conflict and setting the world on a path to endless war.
Leo, who has adopted a stronger tone in recent months and angered US President Donald Trump by criticizing the Iran war, has made a range of impassioned appeals to world leaders in a lengthy document known as an encyclical.
The first U.S. pope called on policymakers to protect workers’ rights and protect children from technology by moving ownership of AI data away from private hands, and to cool competition among AI companies.
“What we need is more active political engagement that can slow things down when everything is accelerating,” Leo said in a text titled “Magnifica Humanitas.”
The Pope called for “a strong legal framework, independent monitoring, informed users and a political system that does not abdicate responsibility.”
Encyclicals are one of the highest forms of teaching from the Pope to the Church’s 1.4 billion members.
Monday’s long-awaited document is about 43,000 words long and has been in the works for most of the time since Leo was elected pope a little more than a year ago.
Pope rejects ‘just war’ theory
The document, which featured AI as a major theme, also decried the number of wars roiling the world, lamented the weakening of multilateral institutions, and warned that military industry interests were driving conflicts.
“The past 60 years have been characterized by astonishingly brutal conflicts, often affecting large numbers of civilian populations,” Leo said in English.
“Humanity is descending into a violent culture of power, where peace is no longer seen as a responsibility to be fulfilled, but as a fragile interval between conflicts,” he said.
At a Vatican event announcing the document on Monday, the co-founder of Anthropic, one of the world’s top AI companies, thanked Leo for addressing the problems posed by disruptive new technologies. He said companies like his faced strong commercial pressures and needed external oversight.
“All frontier AI labs, including Anthropic, operate within a set of incentives and constraints that are sometimes at odds with doing the right thing,” said Chris Olah. Anthropic is the company that makes Claude AI tools.
In his encyclical, Leo also made one of the clearest statements yet by a pope rejecting just war, a doctrine the church has used to assess global conflicts since at least the fifth century.
The doctrine, which generally holds that wars should only be waged to protect against invasion, has been invoked by Trump administration officials, including Vice President J.D. Vance, a Catholic, to defend the Iran war.
“The ‘just war’ theory, so often used to justify wars of all kinds, is now obsolete,” Leo wrote.
“The use of force, violence and weapons reflects the poverty of human relations and always has dire consequences for civilians.”
Mr Leo also expressed concern that leaders could start wars to distract the people from domestic issues.
He said: “We cannot rule out the possibility that some leaders see armed conflict as an effective way to divert attention from domestic issues and as a cynical means of dealing with difficulties.”
Pope apologizes for church’s role in slavery
The Pope said that the use of AI in war “must be subject to the strictest ethical constraints” and that relying on AI systems to make deadly decisions “cannot be tolerated.”
Leo, the 14th pope to choose that name, cited centuries of previous papal teaching on issues of social justice before addressing the ethics of AI systems.
He specifically cited his predecessor, Leo XIII. Pope Leo XIII published a famous encyclical in 1891 calling for improved wages and conditions for workers during the Industrial Revolution.
Pope Leo XIV condemned the “new forms of slavery” endured by those who look after AI systems and by factory workers who produce technological devices such as computers and smartphones in which AI is used.
“In some parts of the world, children and adolescents work in dangerous conditions to crush the raw materials from which rare earth elements are extracted,” the Pope wrote.
“These people’s bodies are scarred, injured and worn out so that the flow of calculation can continue uninterrupted,” he said. “This reality deeply questions the moral conscience of our time.”
The Pope also acknowledged that the Catholic Church did not forcefully condemn transatlantic slavery until the 19th century, and apologized personally.
“This would be a stain on the memory of Christians,” he wrote. “For this reason, in the name of the Church, I sincerely ask for your forgiveness.”
Pope urges world to address AI risks
Leo began his letter by appealing to Catholics and all people of goodwill, saying society must face “serious questions” about how AI is developing and the general direction of global leadership.
Citing the Biblical story of the Tower of Babel, in which a tribe of humans, driven by pride, tried to build a tower high enough to reach heaven, angering God, he said the story illustrates the dangers of any undertaking that “aims to reach heaven without God’s blessing.”
“I ask you, with the heart of a shepherd and a father, to abandon the construction of yet another Tower of Babel and to work together to build the common good,” the Pope said.
Leo urged the world not to give up on addressing the potential risks of AI systems.
“A subtle temptation may emerge: the idea that the problem is too big and we are too small, and therefore that our choices cannot make a difference,” he wrote.
“Certainly, not everyone has the same power to effect change,” Leo says. “But no one is without responsibility. We all have our own sphere of action.”
(Reporting by Joshua McElwee; Editing by Crispian Ballmer and Keith Weir)
