Theologians interviewed by Euronews suggest that the intensifying verbal conflict between Washington and the Holy See raises significant questions regarding Catholic and Christian ethical thinking.
When US Vice President JD Vance embraced Catholicism in 2019, he selected Saint Augustine as his patron saint.
ADVERTISEMENT 
ADVERTISEMENT
At a Turning Point USA event on Tuesday, Vance referenced the legacy of the fifth-century theologian and esteemed Church father to counter Pope Leo XIV’s critique of the conflict in Iran.
The second-ranking official in the White House cautioned the pope to «exercise caution when discussing theological issues,» while defending himself by citing the «over a 1,000-year heritage of just war theory.»
Meanwhile, the Catholic Church’s supreme pontiff was present in the Algerian port city of Annaba, honoring the basilica near the site where St Augustine passed away and was originally laid to rest.
Known as Hippo Regius in Augustine’s era, the location is where the saint penned much of the foundational work that underpins the just war concepts Vance claims to uphold. Pope Leo XIV is notably the first pope from the Augustinian order.
Whether Vance was aware of the pope’s schedule that day is unclear, as his office declined to comment.
Vance was not the only administration official to comment.
A few days prior, US President Donald Trump posted on Truth Social and reaffirmed to the media that Pope Leo XIV was “ineffective on crime» and “poor on foreign policy,” implying that the pope endorsed Tehran’s development of nuclear arms.
However, the pope has not made any statements supporting the Islamic Republic’s nuclear ambitions.
This reaction followed the pope condemning Trump’s threat to annihilate Iran’s “entire civilisation” as “completely unacceptable.”
The next morning, while en route to Algiers aboard the papal plane, Pope Leo XIV replied, “I am not intimidated by the Trump administration nor by speaking forcefully about the Gospel’s message.”
“I will persist in vocally opposing war, seeking to foster peace, encouraging dialogue and multilateral cooperation among nations to pursue just resolutions.”
What the doctrine states
Just war theory, originating from St Augustine and expanded by Thomas Aquinas in Summa Theologiae, prescribes stringent criteria for the ethical deployment of military power.
The threat must be continuous, serious, and undeniable, with a feasible chance of success. Crucially, all other avenues for resolution must be truly exhausted, and the inflicted damage should not surpass the harm it aims to prevent.
In essence, these principles exist to prevent combatants from acting as sole arbiters of their moral rightness.
“The just war doctrine doesn’t simply consider whether a cause seems just,” Joseph Capizzi, Dean of the School of Theology and Religious Studies at the Catholic University of America, explained to Euronews. “As is common knowledge, everyone believes their cause to be just.”
“It acknowledges this widespread conviction but provides a framework to differentiate legitimately just causes of war from those that are not.”
The application of this doctrine has evolved over time. Historically, priests employed it to sanction their rulers’ wars. However, driven by the world wars and nuclear weapons’ advent, the papacy has increasingly applied it to challenge military actions.
“In the past, just war doctrine was frequently utilized by national clergy to authorize their leaders’ wars,” explained Massimo Faggioli, professor of ecclesiology at Trinity College Dublin, to Euronews.
“Currently, it is predominantly — I would say almost exclusively — invoked to argue that a particular military intervention fails to satisfy those standards.”
Writing during the Roman Empire’s decline, St Augustine raised a foundational question on justice, becoming one of Catholic moral thought’s most profound check on power.
“Without justice,” he inquired in The City of God, “what are kingdoms but large gangs of thieves?”
Vance referred to The City of God as “the most profound critique of modern times” he has encountered, greatly influencing his religious perspective and views on domestic and foreign affairs.
Vatican’s history
The administration’s portrayal of Pope Leo XIV as a pacifist lacking understanding of necessary force contradicts both the pontiff’s stance and the Church’s historical record, according to experts.
Prior to his election last year, the pope was a registered Republican. Though critical of the war in Iran, he has expressed support for Ukraine’s entitlement to self-defense.
Past popes have traditionally evaluated context carefully before commenting on conflicts.
The Holy See quietly acknowledged the post-9/11 intervention in Afghanistan as meeting just war criteria, as the US targeted Taliban extremists and Al-Qaeda leader Osama bin Laden.
However, Pope John Paul II opposed both the 1991 Gulf War and 2003 Iraq invasion, not from pacifism, but because last resort had not been demonstrated. The position of Pope Leo XIV on Iran aligns with his predecessors, theologians note.
“To label the pope a pacifist is truly absurd,” said Faggioli. “Vance and Trump accuse the pope of holding a European Catholic view on war, but that is inaccurate.”
“He employs just war doctrine—and American cardinals opposing the Iran war have used this doctrine in ways that differ from Europeans. This represents, in part, an intra-American debate.”
Faggioli further noted the implication of Vance’s statement suggesting the pope should limit himself to morality and avoid foreign policy matters.
“Vance likely belongs to the category of Catholics who reduce morality to sexual ethics,” he explained. “When Vance said the pope should focus solely on morality, he referred to sexual morality, ignoring that war also falls within moral considerations. It certainly does.”
A millennium of tradition and principles
The US bishops alongside other Catholic clergy have not remained silent. On Wednesday, Bishop James Massa, chair of the USCCB Committee on Doctrine, issued a statement supporting the pope’s stance and the Church as a whole.
“A constant principle of this thousand-year tradition is that a nation can legitimately wield the sword only ‘in self-defense, after all peace efforts have failed,’” Massa, auxiliary bishop of Brooklyn, affirmed.
“When Pope Leo XIV speaks as the supreme shepherd of the universal Church, he is not merely providing theological opinions. He proclaims the Gospel and fulfills his role as the Vicar of Christ.”
Experts observe that, unlike previous public clashes with critics of Washington’s view, the Trump administration has found it challenging to deploy its usual strategies to undermine the pope due to his American identity.
“They cannot label him a communist or radical leftist—his theological record does not support such claims,” Faggioli said.
Euronews reached out to several Catholic scholars and institutions for commentary on the Trump administration’s interpretation of just war doctrine, but none agreed to provide on-record comments.
‘A firm teaching of our faith’
On Thursday, during a peace gathering in Cameroon—a nation grappling with its own conflicts—the pope declared, “Woe to those who exploit religion and God’s name for their own military, financial, and political interests, dragging what is sacred into darkness and filth.”
This statement, posted on his official Pontifex account on X, attracted nearly 10 million English-language views by Friday evening.
Capizzi cautioned against interpreting every papal comment as directed solely at Washington. “You are in Cameroon, a continent marked by deep religious strife; this remark has wider relevance.”
Nonetheless, Capizzi emphasized that the Holy Father’s messages address all believers.
“Anyone invoking God, as though God sides with them, must do so with profound reverence and fear,” he stated. “This is a consistent teaching of our faith: that a believer is one who fears God and God’s judgment on their deeds, including the manner in which they speak about God.”
On the same day at the Pentagon, US Secretary of Defense Pete Hegseth led a worship service and recited what he described as a prayer used by Combat Search and Rescue units during the Iran mission.
He introduced it as «CSAR 25:17,» referencing Ezekiel 25:17. However, it closely mirrored the monologue spoken by Samuel L. Jackson’s character Jules Winnfield in Quentin Tarantino’s Pulp Fiction, moments before a murder scene.
The actual biblical passage is much shorter and less detailed. Tarantino’s version was itself adapted from a 1973 Japanese martial arts film.
‘Nothing against the pope’
Trump secured approximately 55% of the US Catholic vote in 2024. A late March poll by Republican Shaw & Co Research and Democratic Beacon Research indicated his approval among Catholics had declined to 48%, with 52% disapproving.
A Fox News survey showed US Catholics opposed military action in Iran by a 10-point margin and criticized Trump’s Iran policy by 20 points. Another NBC poll revealed US registered voters hold the pope in higher regard than the president by 46 points.
On Thursday, Trump told reporters he harbored «nothing against the pope» and is «fully committed to the Gospel,» while continuing to claim Pope Leo XIV endorsed Tehran’s nuclear aspirations.
Trump also indicated his preference for the pope’s brother Louis, residing in Florida: «Louis is wholly MAGA. He understands, unlike Leo (XIV),” he stated.
“If I weren’t in the White House, Leo wouldn’t be in the Vatican,” he reiterated.
The night before, police surrounded the New Lenox residence of another pope sibling, John Prevost, following a bomb threat. Explosive-sniffing dogs found no threat. The investigation is ongoing.
The broader context
According to Faggioli, the confrontation is symptomatic of a longer-standing issue: not merely a domestic dispute over one war but a deeper contest about Christianity’s meaning and its representatives.
“America always embraced a religious self-understanding as a nation, yet presidents traditionally avoided appearing as messianic figures—at least publicly,” he commented.
“Trump exploited America’s secularization vacuum, filling it with a degree of messianism—and some American Christians welcome that.”
“Trumpism represents political messianism. He perceives himself—and is perceived by others—as a divine agent: a political Messiah delivering salvation to America, its people, and Christianity. His conviction is evident in his posts.”
Capizzi, however, believes the president will ultimately reconcile with the Holy See. “I actually view this as an encouraging sign—that it affects President Trump despite his statements and posts.”
“This dialogue demonstrates that the Church maintains its moral authority,” he said.
“It serves as a teaching moment. Catholics and others witness doctrines over a millennium old, reflecting deep contemplation on these issues, underscored by significant moral weight.”
Regarding the pope, John Prevost remarked before these events unfolded, “I do not think he will remain silent for long when he has something to express,” he told the New York Times last year. “He will not just stand by.”