In response to Pope Leo XIV's appeal for leaders of warring nations to return to negotiations, the Trump administration has invoked traditional just war theory to justify its aggressive actions. Vice President JD Vance accompanied his citation of the theory with a controversial remark that the Pope should be careful when discussing theology. Several Catholic archbishops have countered that the war against Iran does not meet the criteria set by just war theory.
Historical Context of Just War Theory
The theory is most associated with Saint Augustine, though attempts to justify war alongside peace ideals predate him. It was formulated when wars were fought face-to-face with primitive weapons like spears and arrows. The theory provides rigorous criteria for a war to be justified, including being a last resort, ensuring the evil caused is not greater than the evil eliminated, having a serious chance of success, and requiring a just cause. However, it was never intended to replace peace as an ideal.
Evolution in Modern Catholic Teaching
Recent Catholic teaching has evolved beyond the medieval theory, yet current discourse on the moral justification of the Iran war often fails to bridge this gap. No recent pope has invoked just war theory to justify war; instead, modern popes have condemned war. Pope Benedict XV, in his first encyclical during World War I, lamented the horrors of modern weapons. Pope John XXIII, in Pacem in Terris, argued that disputes should be resolved through negotiation, citing the destructive force of modern weapons. Pope Paul VI famously declared, "No more war, war never again!" and insisted, "If you want peace, work for justice."
Pope John Paul II strongly criticized the American invasion of Iraq, calling it a "defeat for humanity." Cardinal Joseph Ratzinger, later Pope Benedict XVI, explained in 2003 that given new weapons causing destruction beyond combatants, one must question whether just war is still licit.
Pope Francis on Modern Warfare
In Fratelli Tutti, Pope Francis questions whether nuclear, chemical, and biological weapons, along with new technologies, grant war uncontrollable destructive power over innocent civilians. He concludes it is very difficult today to invoke rational criteria from earlier centuries to speak of a just war.
The just war theory remains valuable for setting high hurdles for moral justification of war. However, a true disciple of Jesus today must go beyond it and embrace the gospel of peace. The theory was formulated with primitive weapons, but the atomic bombs dropped on Hiroshima and Nagasaki killed nearly 200,000 people, mostly civilians. Today's weapons dwarf those bombs, making the 1945 bombs seem like firecrackers in comparison.
