The Pope Is Right—The US-Israeli War With Iran Violates Just War Theory

On April 10, Pope Leo XIV posted on Twitter-X: “God does not bless any conflict. Anyone who is a disciple of Christ, the Prince of Peace, is never on the side of those who once wielded the sword and today drop bombs. Military action will not create space for freedom or times of #Peace, which comes only from the patient promotion of coexistence and dialogue among peoples.”

The Pope’s condemnation of war drew the ire of the self-proclaimed “Peace President” and his allies. On Truth Social, President Donald Trump described the Pope as “Weak on Crime, Weak on Nuclear Weapons” and “terrible for Foreign Policy.” At a Turning Point USA event, Vice President JD Vance remarked, “When the pope says that God is never on the side of people who wield the sword, there is more than a 1,000-year tradition of just war theory.” Speaker of the House Mike Johnson (R-La.) was likewise “taken a little bit aback.” He told reporters: “It’s a very well-settled matter of Christian theology. There’s something called the just war doctrine.”

Yet just war is precisely the Pope’s point. As Bishop James Massa, the chairman of the US Conference of Catholic Bishops’ Committee on Doctrine, said in a statement:

For over a thousand years, the Catholic Church has taught just war theory and it is that long tradition the Holy Father carefully references in his comments on war. A constant tenet of that thousand-year tradition is a nation can only legitimately take up the sword "in self-defense, once all peace efforts have failed" (Catechism of the Catholic Church, no. 2308). That is, to be a just war it must be a defense against another who actively wages war, which is what the Holy Father actually said: "He does not listen to the prayers of those who wage war."

Ultimately, this appeal to Just War Theory by Vance and Johnson is a desperate retort from a historically sinful administration. To date, Trump has authorized military strikes in 10 countries: Afghanistan, Iraq, Yemen, Pakistan, Somalia, Libya, Syria, Venezuela, Nigeria, and Iran. Currently, the Pentagon is reportedly preparing for military action against Cuba—a nation that Trump has repeatedly threatened to “take.” This invasion would come months after the Trump administration imposed a total oil blockade that is causing widespread suffering and starvation there. No interpretation of Just War Theory would ever justify such rampant and senseless violence.

Just War Theory

Modern versions of Just War Theory are split into three components: first, jus ad bellum, or the conditions under which a nation may justifiably wage war. This includes: (i) a just cause (e.g., self-defense, protecting the innocent), (ii) war must be a last resort, (iii) right intention (i.e., the war must be conducted for the sake of justice—not self-interest or personal gain), and (iv) declared by a proper authority.

The violence and suffering that the US and Israel have caused can never be undone. Yet, we can and must hold the responsible parties accountable.

The second component is: jus in bello, or how a just war is waged. This includes: (i) distinguishing between civilians and combatants and (ii) proportionality (i.e., deploying the minimum amount of violence necessary to achieve one’s goal—no matter how righteous the cause, excessive destruction is unjust).

Finally, the third component is: jus post bellum, or how nations ought to act once the fighting has stopped, including during a ceasefire. This includes: (i) not punishing civilians, (ii) respecting the rights and traditions of the defeated, (iii) not exploiting the defeated nation, and (iv) rehabilitating the aggressor to avoid future violence.

Trump’s wars consistently fail these criteria. Consider the US-Israeli war with Iran.

Jus Ad Bellum

Trump alleges that this war was necessary to stop Iran from developing nuclear weapons. However, he had previously alleged that Operation Midnight Hammer had “significantly degraded Iran’s nuclear program.” There is no evidence that Iran was developing a nuclear weapon, had ambitions to develop nuclear arms, or that they posed an immediate threat to the US. There is no just cause here.

This war was also not a last resort. Not only was Iran negotiating with the US, but they also made major concessions to the Trump administration regarding their nuclear program. Omani Foreign Minister Badr bin Hamad Al Busaidi, who was mediating these talks, said, “I have seen a lot of flexibility on both sides, and I believe it’s really a matter of just keeping at it, keeping negotiating to get that to that finishing line.” Trump, however, unilaterally decided to stop these productive talks based on a “feeling”—not necessity.

The Trump administration has provided several, often conflicting, reasons for this war. Notably, Israeli Prime Minister Benjamin Netanyahu expressed that he has “longed” for this war “for 40 years.” President Trump has repeatedly insisted that, “If it were up to me, I’d take the oil, I’d keep the oil, it would bring plenty of money.” This is, after all, what he did in Venezuela after kidnapping President Nicolás Maduro. As Trump put it, after (rightfully) not winning the Nobel Peace Prize, he “no longer feel[s] an obligation to think purely of Peace.” His actions in Iran, Venezuela, and elsewhere reflect this. They are not guided by the pursuit of justice or peace, but rather personal and financial gain.

As for proper authority, the Constitution is clear: Congress alone has the power “to declare War.” No congressional approval means no just war.

Jus In Bello

On the very first day of the war, the US struck a girl’s elementary school killing more than 175 people. The International Federation of Red Cross and Red Crescent Societies reports that at least 1,900 people have been killed and 20,000 injured in Iran since the start of US-Israeli attacks. On March 9, Iranian Deputy Health Minister Ali Jafarian reported that 52 health centers, 18 emergency service locations, and 15 ambulances had been damaged or destroyed. US-Israeli strikes also “completely destroyed” a synagogue in Tehran and at least 30 universities have been impacted. Trump has even gone as far as to threaten, “A whole civilization will die tonight, never to be brought back again.” Clearly, no distinction between civilians and combatants is being observed.

In clear violation of international law, Secretary of War Pete Hegseth pledges “no quarter, no mercy for our enemies.” On March 2, he remarked: “No stupid rules of engagement, no nation-building quagmire, no democracy building exercise, no politically correct wars. We fight to win, and we don't waste time or lives.” There will be “no apologies, no hesitation” for “we are not defenders anymore. We are warriors, trained to kill the enemy and break their will.” By his own admission, Trump is likewise “not at all concerned about war crimes.” The point here is clear: Excessive violence is this administration’s first resort.

Jus Post Bellum

At the time of this writing, the US and Iran have agreed to a ceasefire. After the first round of talks, Vance, who was heading the US delegation, said Iran chose “not to accept our terms.” He remarks, “The bad news is that we have not reached an agreement, and I think that’s bad news for Iran much more than it’s bad news for the United States of America.” Vance’s wording makes clear that the US is not negotiating with Iran as equals. This is unsurprising. Throughout this conflict, Trump has repeatedly referred to Iran’s leaders as “lunatics” and “crazy bastards.” Secretary of State Marco Rubio has described them as “lunatics,” “insane,” and “religious zealots.” This lack of respect for the Iranian people will only serve to further tensions and make a lasting peace less possible.

Indeed, the US initially sought to escalate hostilities during this ceasefire by imposing its own blockade on the Strait of Hormuz. The purpose here was clear: By blocking their oil exports, the US was hoping to coerce Iran into submission. Because of sanctions, the Iranian economy is already fragile—a blockade could have major financial and humanitarian consequences. Even during a ceasefire, the Trump administration’s first instinct is to cause collective suffering.

As part of the Lebanon ceasefire, Iran has agreed to open the Strait; however, Trump has declared that the American blockade on Iranian ships and ports “will remain in full force.”

Ultimately, this is not a war of self-defense. It is not a preemptive war against a legitimate threat. It is a war of glory and conquest. It is a war of sin.

The violence and suffering that the US and Israel have caused can never be undone. Yet, we can and must hold the responsible parties accountable. Trump, Netanyahu, and everyone in their administrations who enabled this war must be brought to justice. They have shown themselves time and time again to lack the moral character necessary to lead a nation. Justice likewise demands that reparations be made. While no compensation can ever make up for the loss of innocent life, Iran must be provided with the tools and resources necessary to rebuild their nation.

On April 16, Pope Leo XIV remarked, “The world is being ravaged by a handful of tyrants, yet it is held together by a multitude of supportive brothers and sisters.” Once again, the Pope is right—we must never stop striving toward building a more peaceful and just world. A world where people are elevated, not buried under rubble; a world where children grow up safe and sound without fear of “Epstein’s Fury”; a world where love, compassion, and respect for others trumps war, death, and destruction.