Abstract

This article examines the doctrinal status of just war in the contemporary teaching of the Catholic magisterium. Some passages from Pope Francis’s 2020 encyclical Fratelli tutti, On Fraternity and Social Friendship appear to exclude the just war idea from the social doctrine of the Catholic Church. To gauge whether this is so, the article establishes a baseline comparison to the seminal teaching of Thomas Aquinas on peace and just war. Both St. Thomas and Pope Francis proceed from the assumption that “war” designates a sinful violation of peace. They appear to differ, however, on the question whether a positive meaning should be ascribed to the Roman term bellum justum. To understand if this divergence is purely verbal or involves a substantive disagreement, I consider why Pope Francis’s predecessors have (since the mid-twentieth century) abstained from employing the expression “just war” in their official documents. Finally, Pope Francis’s emphatic statement that St. Augustine ‘forged a concept of “just war” that we no longer uphold in our own day’ is interpreted in light of the passage from his Epistle 229 to Darius that Francis references in Fratelli tutti.