Catholic Social Thought and War explores the Church’s evolving moral reflection on war, peace, and nuclear weapons through the lens of Catholic social teaching. Drawing on Gaudium et Spes from the Second Vatican Council, the U.S. Bishops’ pastoral letter The Challenge of Peace, and the teachings of Pope John Paul II, Pope Benedict XVI, and Pope Francis, this resource provides a comprehensive overview of the Catholic approach to just war theory, Christian nonviolence, and integral disarmament

The reflection examines the two moral traditions embedded in Catholic thought—just war theory and pacifism—and highlights how modern warfare, especially the development and use of nuclear weapons, has challenged traditional frameworks. Vatican II’s strong condemnation of indiscriminate destruction and the arms race marked a significant turning point in Catholic teaching. Subsequent Church leaders have increasingly emphasized nonviolence, global solidarity, and the urgent need for nuclear disarmament.

The resource also addresses contemporary issues, including:

• Nuclear deterrence and the morality of nuclear weapons
• The global arms trade and its impact on the poor
• Terrorism and drone warfare
• The humanitarian and environmental consequences of modern conflict
• The Church’s support for international cooperation and the Treaty on the Prohibition of Nuclear Weapons

Key Principles of Catholic Social Teaching

Grounded in key principles of Catholic social teaching—human dignity, the common good, solidarity, care for creation, and the option for the poor—this reflection invites readers to examine how faith shapes moral decision-making in times of war. It includes discussion questions for classroom or parish use, concrete faith-in-action steps, and a closing prayer for peace.

Authored by Fr. Fred Kammer, S.J., a Jesuit priest and longtime leader in Catholic social ministry who has served as director of the Jesuit Social Research Institute at Loyola University New Orleans, this reflection brings pastoral insight and decades of experience in Catholic social ethics to one of the most urgent moral questions of our time

Ideal for Catholic educators, campus ministers, parish leaders, and students studying Catholic social teaching, this resource provides both theological depth and practical application for understanding the Church’s call to peace in a nuclear age.