In Magnifica Humanitas, Pope Leo called the just war theory “out of date.” Does it matter? What is the just war theory? Why does he say it is “out of date”? What are the consequences? What would a new framework for Catholic teaching on legitimate defense, violence and nonviolence look like? How can we amplify our understanding of Gospel nonviolence to explore nonviolent options for protection and security?

Following are some resource to help advance this conversation.

Videos

“Answering Pope Leo’s nonviolent appeal,” June 2026

Panel at the founding of the Catholic Institute for Nonviolence, September 2024

Books published by Pax Christi International

Articles by Dr. Eli McCarthy

Pax Christi USA resources

Ben Salmon No Just War Registry for Conscientious Objectors: Although many faith traditions hold a conscientious objector registry for congregants, until now, none existed specifically for Catholics who do not wish to participate in war-making. Through conversation and prayer, this project was intentionally and collaboratively crafted by the Pax Christi USA National Council and staff to provide a dedicated framework to equip young Catholics in documenting and affirming their conscientious objection to war.

Catholic Nonviolence Initiative (CNI) Fall Series – video recordings and study guides: Offered especially for students.

Vow of Nonviolence

The Vow of Nonviolence was written by Pax Christi USA co-founder Eileen Egan and Pax Christi USA Ambassador of Peace Fr. John Dear. It can be pronounced privately, with a local peace community, as part of a parish liturgy, or any other way that suits you. Many profess the Vow each year as part of their New Year observance. Pax Christi International has translated it into eight languages. Read more here.