Pope Leo XIV warns AI and nuclear arms

Pope Leo XIV denounced nuclear deterrence as mistaken and warned that a 'paradise of machines' risks undermining humanity. He issued the warning on Friday, September 25, 2026, during his opening speech to French President Emmanuel Macron and diplomats at the Élysée Palace, posing fundamental questions about what it means to be human in artificial intelligence and a nuclear arms race.

The pope said the nuclear deterrence doctrine was 'mistaken' as it merely fuels a new arms race. He reaffirmed the Vatican's opposition to nuclear weapons. "Peace is not a balance of power; rather, it is built day by day through dialogue and justice," Pope Leo XIV stated.

Historic visit shows Vatican-France engagement

This four-day state visit is the first by a pope to France in 18 years. Church bells tolled across the country as his charter flight landed at Paris' Orly airport. The welcome showed a surprising level of interest, with thousands lining his motorcade route and waving flags. The Vatican estimated about 300,000 people came out to see the pontiff on Friday. Some braved hours of unseasonable heat for a glimpse.

Later on Friday, the pope was scheduled to visit UNESCO headquarters, celebrate vespers at the newly reopened Notre-Dame cathedral, and preside over a large youth vigil at the Paris stadium.

Macron’s political context and papal appeal

For Macron, hosting the American pope serves as a capstone. He is barred from seeking a third term in elections just seven months away, and his approval ratings are near record lows. Analysts noted the symbolic value. Charles Mercier, director of history and sociology of Catholicism studies at Paris EPHE university, said for a president at the end of his mandate, it can be important to be alongside the pope and capture a part of his popularity.

Macron smiled broadly as Leo spoke French and thanked the pope for visiting, saying his extended visit was moving.

Clash over bioethics and Christian identity in France

In his speech, Pope Leo XIV emphasized Europe's Christian roots and reminded France of its deep Christian roots. He called for the nation to remember that the right to life is the 'indispensable foundation of every other human right.' This stance directly opposes recent French legislation.

The right to abortion was enshrined in the French constitution in 2024. Also, French lawmakers recently gave final approval to a bill allowing adults with incurable illnesses to receive lethal medication. The French Catholic hierarchy strongly opposed both measures, in keeping with Catholic teaching on protecting life from conception to natural death.

The pope stressed that authentic secularity, while enshrined in France's constitution, should not exclude religion from the public sphere or education.

AI ethics and calls for responsible innovation

From the start of his pontificate, Leo has identified artificial intelligence as one of humanity's greatest challenges. He dedicated his first encyclical, 'Magnificent Humanity,' to the topic, calling for robust regulation and for AI developers to work for the common good.

He appealed to AI developers and political regulators to slow down. If we are to avoid losing our humanity amid a 'paradise of machines' invading and conditioning our daily lives, there is an urgent need for education in ethical discernment, he said. The pope noted that several top AI companies seem to have taken his appeal to heart recently. He expressed hope that the dialogue with tech companies would continue, saying many are open to ensuring AI serves as a tool rather than destroying humanity.

He also highlighted a paradox, noting that while 'intelligence' is attributed to computational systems, society struggles to recognize the inalienable dignity of human persons, who are judged by efficiency and discarded when no longer productive.

At an evening prayer service at Notre-Dame, Senegalese Sister Antonia Faye expressed the sentiment of many worshippers. "To see him, praying with us, it comforts us in our faith and on our path," she said. Thousands of worshippers later cheered the pope as he prayed at a stadium near Paris, calling those gathered the 'saints of France.' Pope Leo XIV will continue his four-day visit with engagements at UNESCO, Notre-Dame cathedral, and a youth vigil at the Paris stadium.