Nicolai Haugsted
The Pope goes against old teachings of the church.
One of Christianity’s most influential teachings on war has come under direct challenge from the head of the Catholic Church.
Pope Leo has used his first major papal document to reject the long-standing “just war” doctrine as a framework for modern conflicts, arguing that humanity now possesses better tools for preventing and resolving wars.
Statement marks one of the most significant interventions yet from the new pope on questions of global security, military conflict and international diplomacy.
“Just War” No Longer Fits Modern Conflicts
Writing in his new encyclical, Magnifica Humanitas (“Magnificent Humanity”), Leo argued that a concept used by theologians, governments and military leaders for more than 1,500 years no longer reflects today’s realities.
“The ‘just war’ theory which has all too often been used to justify any kind of war, is now outdated,” the pope wrote.
“Humanity possesses far more effective and capable tools for promoting human life and resolving conflicts, such as dialogue, diplomacy and forgiveness,” he added.
Doctrine traces its roots to St. Augustine, one of the most influential figures in early Christianity. Augustine argued that wars could only be morally justified under strict conditions, including the goal of restoring peace rather than pursuing conquest or revenge.
Growing Concern Over Modern Warfare
Experts involved in presenting the document said Leo’s comments reflect concern over how warfare has evolved.
Anna Rowlands, a British academic who participated in the Vatican presentation, said the pope is responding to “a new age of changing conflict, now increasingly tech driven.”
“It is a strong statement about the need for (just war theory) to be placed in a renewed wider context of criteria for building peace and resolving conflict,” she said.
Document also calls for stronger international oversight of artificial intelligence systems and contains what observers describe as the clearest apology yet for the Church’s historic role in supporting transatlantic slavery.
Clash With Political Leaders
Debate over the “just war” doctrine has gained renewed attention during recent international conflicts.
US Vice President JD Vance, a Catholic, has cited the theory while defending military action against Iran.
Earlier this year, Vance publicly referenced the doctrine after criticism from the Vatican regarding modern warfare.
Chicago Cardinal Blase Cupich, a close ally of Pope Leo, said the problem lies in how political leaders have increasingly used the concept.
“We have to make clear that the just war theory was always meant to be a restraint, not a permission slip which sadly some are misusing to justify their decisions to go to war rather than seek the ways of peace,” Cupich said.
Military Academies Still Teach the Theory
Despite Leo’s criticism, the doctrine remains deeply embedded in military education around the world.
Augustine’s principles continue to form part of curricula at institutions including West Point, the US Naval Academy and the US Air Force Academy.
Supporters of the pope’s position argue that modern conflicts have exposed the limitations of a framework developed more than 15 centuries ago.
Marie Dennis, former leader of the international Catholic peace movement Pax Christi, welcomed the pope’s intervention.
“Pope Leo joins millions of others around the world, including in the U.S., who see hope in the proven effectiveness of nonviolent strategies for protecting democracy, transforming conflict, and legitimate defense,” she said.
Remarks are likely to fuel further debate inside both religious and political circles, particularly as wars in multiple regions continue to shape international security discussions.
