Donald Trump and JD Vance have been publicly scolding Pope Leo over the Catholic Church's teaching on just peace and just war. What are these teachings? How do just peace and just war teachings fit together? What are the Church's positions on current conflicts, such as Russia's war on Ukraine, and U.S. attacks on Iran? How have Popes Francis and Leo advanced the Catholic understanding and use of the just war principles? What are the criteria for peacemaking, especially in a nuclear age?

Dr. Maryann Cusimano Love is Chair of the Politics Department of The Catholic University of America in Washington, DC. She serves as a consultant to the Holy See Mission at the United Nations, where she participates in the UN negotiations on nuclear weapons, and Artificial Intelligence and Lethal Autonomous Weapons systems. Dr. Love is a New York Times best selling author; she lives on the Chesapeake Bay with her husband Richard Love and their three children.