On September 25, 2026, at the Élysée Palace in Paris, Pope Léon XIV and French President Emmanuel Macron presented contrasting views on the role of nuclear weapons in international relations. During the Pope’s visit to France, which lasted from September 25 to 28, the first day of the trip featured a significant political moment as the pontiff addressed Macron, French officials, and the diplomatic corps. Léon XIV, who holds dual citizenship of the United States and Peru, challenged France’s nuclear deterrence strategy, which aims to protect not only France but also other European nations. This marked a sharp philosophical and strategic difference between the Vatican and the French government’s approach to global security. The Pope’s speech was not a general appeal for peace but a detailed critique of the concept of "security weapons." He relied on the teachings of previous popes, especially the Pacem in Terris encyclical from 1963, to argue that the belief that nuclear weapons ensure security is fundamentally flawed. This directly contradicted France’s long-standing view that its nuclear arsenal is essential for national survival and regional stability. The Vatican’s stance suggests that peace cannot be achieved through a balance of military power alone. Léon XIV also warned about the risks of a new arms race and called for a world order based on dialogue and justice rather than deterrence. He urged France to take a leadership role in reducing global arsenals and promoting multilateral diplomacy. Macron, while acknowledging the Pope’s call for peace, emphasized the need for pragmatic policies in a world marked by rising tensions and powerful nations with superior military capabilities. In response, Macron reaffirmed France’s commitment to peace, international law, and multilateralism, framing these as guiding principles for French foreign policy. He argued that the reality of global politics requires a strong national defense, particularly in the face of aggressive powers. For France, nuclear deterrence is not a rejection of diplomacy but a means to ensure the country can negotiate from a position of strength. The exchange between Macron and Léon XIV highlighted a deeper debate about the future of Western democracies. The Vatican advocates for a world based on moral principles and disarmament, while France defends the necessity of nuclear weapons in a fragmented and dangerous geopolitical landscape. This dialogue, which took place in September 2026, set the stage for an ongoing tension between ethical and pragmatic approaches to global security.