By Evan Lee Salim 
By Richard Haass
June 19, 2026
VATICAN CITY — As the landscape of global warfare shifts from the traditional, state-on-state battlefields of the 20th century to the murky, asymmetric, and increasingly automated conflicts of the 21st, the Roman Catholic Church is preparing to confront the moral foundations of modern violence. Pope Leo XIV has announced an extraordinary consistory—a formal assembly of the College of Cardinals—to be held at the Vatican in late June. While the gathering will address several matters of ecclesiastical governance, its centerpiece is an urgent, high-level re-examination of the "just war" doctrine.
For centuries, the Church has relied on the framework established by thinkers like St. Augustine and St. Thomas Aquinas to delineate when, and how, a nation may morally engage in armed conflict. However, in an era defined by drone warfare, artificial intelligence, and the systematic blurring of lines between combatants and civilians, Pope Leo XIV has signaled that the time for a theological and ethical overhaul is long overdue.
Main Facts: The Vatican’s Pivot
The upcoming consistory is not merely a symbolic meeting; it is an attempt to align centuries-old moral theology with the harsh realities of a world in crisis. The doctrine of bellum iustum (just war) traditionally rests on several pillars: jus ad bellum (the right to go to war) and jus in bello (the conduct within war).
Pope Leo XIV’s intervention comes at a time when civilian casualties in international conflicts have reached levels not seen since the Second World War. The Vatican’s stated objective for the June sessions is to ask "necessary, uncomfortable questions" about whether current interpretations of the doctrine have become a shield for powers to justify aggression rather than a sword to protect the innocent. The Holy See is expected to push for a more restrictive interpretation of "proportionality" and "last resort"—two pillars of the doctrine that have been severely strained by modern tactical advancements.
Chronology of a Shifting Doctrine
The evolution of the Church’s stance on war has been marked by significant historical milestones, each responding to the technological and geopolitical changes of its day.
- 4th Century (St. Augustine): The foundational period. Augustine posited that war could be a necessary evil if conducted by a legitimate authority for a just cause, such as defending the innocent.
- 13th Century (St. Thomas Aquinas): Aquinas refined these concepts into a formal structure, adding the requirement of "right intention."
- 1945–1960s (Post-WWII): Following the horrors of the Holocaust and the atomic bomb, the Church began to emphasize the total prohibition of indiscriminate killing, culminating in the teachings of the Second Vatican Council.
- 2000s–2020s: The rise of the "War on Terror," the proliferation of non-state actors, and the advancement of autonomous weapons systems created a "grey zone" in ethics.
- June 2026: Pope Leo XIV convenes the extraordinary consistory to address the potential obsolescence of traditional definitions in the face of cyber-warfare and AI-driven combat.
Supporting Data: The Cost of Modern Conflict
The urgency of the Pope’s initiative is underscored by sobering global statistics. According to international monitoring groups, the percentage of civilian casualties in major conflicts has trended upward over the last two decades.
- Urban Warfare: In recent years, more than 90% of casualties in urban combat zones have been non-combatants, a statistic that challenges the traditional understanding of "collateral damage."
- The Technological Gap: The deployment of unmanned aerial vehicles (UAVs) has removed the physical risk to the aggressor, which some ethicists argue lowers the barrier to entering a conflict. The Church is particularly concerned that the "distancing" of war via technology erodes the moral gravity of taking a human life.
- Displaced Populations: As of early 2026, the UN High Commissioner for Refugees estimates that the number of people displaced by conflict has reached a historic peak of over 130 million, a direct result of wars that are increasingly fought in populated centers.
Official Responses and Stakeholder Perspectives
The Vatican’s announcement has triggered a complex reaction from the international community.
The Vatican’s View:
Cardinal Pietro Parolin, Secretary of State, recently hinted that the consistory would likely move toward a "presumption against war." He noted that "the classical conditions for a just war are almost impossible to meet in the context of modern military technology. We must ask if we are moving toward a theology of ‘just peace’ rather than ‘just war.’"
Global Diplomatic Reaction:
Major powers, particularly those with permanent seats on the UN Security Council, have expressed caution. Diplomats in New York and Geneva suggest that while the Church’s moral leadership is valued, the practical application of a revised doctrine could create friction with national security strategies. "We respect the Holy See’s moral authority," said one NATO-affiliated diplomat, "but the reality of deterrence requires a flexibility that theological frameworks may not always accommodate."
Academic and Theological Discourse:
Scholars at the Pontifical Gregorian University are divided. Some argue that the doctrine is a flexible, living tradition that can be adapted; others suggest that the concept of "just war" has been so badly abused by political leaders that it should be abandoned in favor of a strict pacifist framework.
Implications: A New Era of Moral Diplomacy
The outcome of this consistory could have profound implications for global geopolitics and the role of the Church as a moral arbiter.
1. Re-evaluating Sovereignty
If the Church formally tightens the definition of "just war," it may challenge the concept of Westphalian sovereignty. A re-evaluation could imply that the international community has a greater moral obligation to intervene when a war fails to meet the updated criteria, regardless of national borders.
2. The AI and Cyber Question
The consistory is expected to address the "moral agency" problem. If an AI system makes a decision to strike a target, who is morally responsible? The Vatican is likely to propose that no lethal force should ever be initiated without meaningful human intervention, a stance that could put the Church at odds with the rapid military modernization programs of several major powers.
3. The Shift to "Just Peace"
The most radical implication is a potential pivot from bellum iustum to a doctrine of pax justa (just peace). This would involve a shift in the Church’s focus from regulating how wars are fought to aggressively advocating for systemic prevention, mediation, and reconciliation. By declaring that modern war is inherently unjust, the Church could become a more powerful, if polarizing, voice in global peace negotiations.
Conclusion: A Call to Conscience
As the College of Cardinals gathers in Rome, they carry the weight of a world weary of persistent conflict. The "just war" doctrine has long served as a bridge between the ideal of peace and the reality of human fallibility. Whether that bridge can be reconstructed to withstand the pressures of the 21st century remains to be seen.
Pope Leo XIV’s initiative is a clear signal that the status quo is no longer tenable. By forcing a dialogue on the ethics of modern violence, the Vatican is asking the world to look beyond the strategic and tactical advantages of war and consider the existential cost. Regardless of the specific changes to the doctrine, the consistory represents a profound moment of reflection for a world that has, in many ways, forgotten how to wage war—or peace—with a clean conscience.
The debates in late June will not end the wars currently raging across the globe, but they will establish a new moral baseline. In an age of machines and mass displacement, the Church’s willingness to re-examine its oldest tenets may prove to be the most significant moral development of the decade. The world will be watching, waiting to see if the Vatican can turn its theological rigor into a catalyst for a more restrained and humane global order.
Nana Muazin 
Asep Darmawan 
Lina Irawan 