On May 25th, Pope Leo XIV published his encyclical titled Magnifica Humanitas, which takes a drastically different stance on international conflict than previously expressed by the Catholic Church. In the encyclical, Leo wrote that just war theory, a centuries old list of criteria determining how to wage war morally, is “outdated,” and instead urges reliance on peaceful and diplomatic forms of conflict resolution. According to Reuters, this first major document released by Leo expresses a different messaging than historically seen from the Holy See. Other sections of the encyclical warn about the dangers of A.I. and provide the clearest formal apology for the Vatican’s role in the Atlantic Slave Trade.
Leo’s outspoken repudiation of unnecessary violence drew criticism from top U.S. officials, including President Trump and Vice President Vance. Trump, following the pope’s denunciation of the war in Iran, called Leo “terrible for foreign policy,” and claimed that the pope is arguing for an Iranian nuclear program. Pope Leo’s disdain for American belligerence in Iran falls in line with established beliefs and teachings within the Catholic Church, despite Trump’s cries of politicization of the papacy. Comparatively, the Trump administration has relied on religious messaging in the previous months, with Secretary of Defense Pete Hegseth asking for Americans to pray for victory “in the name of Jesus Christ,” and the Commander in Chief stating that God would approve of his forays into Iran (Associated Press).
The timing of Pope Leo’s disapproval of just war theory is important and powerful. After a year of interventions or threats in Venezuela, Iran, Greenland, Cuba, and more, U.S. officials have claimed “prevention of aggression” in order to curb criticism of their actions abroad. Vice President Vance even employed the just war theory to fight back against Leo’s disagreements with American involvement in Iran, warning the pope to “be careful when he talks about matters of theology,” (Reuters). Choosing this moment in time to denounce the theory places Pope Leo in direct opposition to President Trump and his foreign policy. This statement acts as a never-before-seen direct reproach of a head of state by the Holy See.
Pope Leo’s power as a symbol for Catholics everywhere provides him the opportunity to impact decision making around the globe. Catholicism is present in every corner of the world, with myriad important international figures following the word of the Vatican, including Vice President Vance. This statement against archaic justifications of violence represents the future potential of the Catholic Church, and similar international religious entities, to act as bastions of peace and non-violent conflict resolution.
