Pope Francis has characterized the concept of “just war”—a doctrine long defended by the United States—as “outdated” in his first encyclical, a papal manifesto that establishes his theological priorities and signals potential friction with Washington over military ethics and intervention doctrine.
The 84-year-old pontiff, who was born in Argentina but holds Argentine citizenship, released the encyclical on Monday with a primary focus on artificial intelligence and its societal implications. However, embedded within the comprehensive document is a forceful rejection of the philosophical framework that has underpinned American military policy for decades. The timing and prominence of this critique in Francis’s inaugural encyclical underscores the centrality of anti-war messaging to his papacy, a position that has previously generated diplomatic tensions with successive U.S. administrations.
The “just war” theory—rooted in Christian theology dating back to Augustine and Thomas Aquinas—posits that military intervention can be morally justified under specific conditions: legitimate authority, just cause, right intention, probability of success, and as a last resort. The United States has historically invoked this framework to justify military campaigns in Iraq, Afghanistan, Syria, and elsewhere. By declaring this doctrine obsolete, Francis is challenging the philosophical scaffolding supporting American military interventionism at a moment when U.S. defense spending and military commitments remain at historically elevated levels across multiple theaters.
Francis’s critique appears in a document titled “Deus Caritas Est” (God Is Love), though sources differ on the exact title. The encyclical represents the Pope’s most authoritative and comprehensive teaching statement, carrying particular weight in Catholic theology and global church policy. His inclusion of this anti-war message alongside extensive passages on artificial intelligence suggests Francis views both as existential concerns for humanity. The Pope has previously warned that AI could become an instrument of war and control, linking technological advancement to broader questions of human dignity and conflict.
The criticism reflects Francis’s consistent positioning as a voice of moral skepticism toward military solutions. Since his election in 2013, the Argentine pontiff has repeatedly called for dialogue over warfare, questioned the morality of arms sales, and visited conflict zones to advocate for peace. His predecessors, including John Paul II, maintained more ambiguous relationships with the just war tradition, particularly during the Cold War when papal doctrine navigated geopolitical complexities. Francis, by contrast, has adopted an increasingly explicit rejection of military justifications across his papacy.
The encyclical’s focus on AI governance alongside its anti-war positioning reflects the Pope’s concern that technological power—like military power—requires moral frameworks rooted in human rights and dignity rather than state interest or strategic advantage. Church sources indicate Francis views both unregulated artificial intelligence and unconstrained military doctrine as threats to human flourishing. This dual emphasis may signal Francis’s intention to position the Catholic Church as a moral counterweight to both Silicon Valley and the Pentagon in coming years.
U.S.-Vatican relations have experienced periodic strain during Francis’s tenure, particularly over migration policy, religious freedom in authoritarian contexts, and foreign intervention. The State Department has not yet formally responded to the encyclical’s contents. However, the denunciation of just war doctrine may generate discussion within American Catholic circles, particularly among conservative intellectuals and policymakers who have cited Catholic moral tradition in support of military interventions. Some U.S. bishops have historically defended just war reasoning; Francis’s explicit rejection could influence internal church debate on this question.
Looking forward, the encyclical’s anti-war messaging is likely to shape Francis’s diplomatic engagement on global conflicts, particularly Ukraine and Middle Eastern crises where the Pope has already advocated for ceasefire negotiations. Whether and how U.S. officials engage with the just war critique will test the Vatican’s diplomatic relationship with Washington. The document signals that Francis intends to use his remaining years as pontiff to push the global church toward a more categorical pacifism—a position that will inevitably collide with security imperatives articulated by NATO and other Western military establishments. The broader question remains whether papal moral authority, particularly on military ethics, retains influence in an era of rising geopolitical competition and technological disruption.
