Pope Leo XIV called on governments to slow the pace of development of artificial intelligence systems in the first major document, Monday, May 25, 2026, warning that they spread disinformation, fuel conflicts and push the world down a path of endless wars. He directed Liu, who has hardened his rhetoric in recent months and angered U.S. President Donald TrumpAfter criticizing the war on Iran, Trump made a series of impassioned appeals to world leaders in a lengthy text known as the Pope's First Encyclical Message.
The first pope of the United States called for the ownership of AI data not to be exclusively in the hands of the private sector, and urged policymakers to protect workers' rights and ensure the safety of children from the dangers of this technology, and to reduce competition among AI companies.
"What we need is more effective political engagement that is able to slow things down when everything is in acceleration," he said in the letter, which is titled "Wonderful Humanity," calling for "appropriate legal frameworks, independent oversight, knowledgeable users and a political system that does not abdicate its responsibilities."
The papal encyclical is one of the highest forms of ecclesiastical teaching to the church's 1.4 billion followers, and the long-awaited 43,000-word document has been in the works since Leo was elected pope a little more than a year ago.
Pope rejects "just war" theory
The document, which focused mainly on artificial intelligence, denounced the wars ravaging the world and lamented the weakness of multilateral organizations, warning that the profits of the arms industry are one of the main drivers of conflicts.
"The past 60 years have seen conflicts that have been marked by remarkable brutality, often involving the civilian population on a large scale," Liu said in the text.
"Humanity is slipping into a culture of violence based on force, and peace is no longer seen as a responsibility to be assumed, but as a fleeting and fragile truce between conflicts," he said.
Liu offered one of the clearest papal positions rejecting the theory of just war, a doctrine adopted by the Church since at least the fifth century to assess international conflicts.
Trump administration officials, including Vice President Jay Smith, were cited. De Vance, a Catholic, adopts this doctrine, which generally states that wars should only be waged in defense against aggression, to justify war against Iran.