An interesting result of President Donald Trump’s strange and mostly one-sided feud with the pope is that there is something of a debate, through the lens of Catholic theology, about whether the US and Israel’s war on Iran is a “just war.” Without restating the minutiae of Trump’s direct attacks on Pope Leo XIV and Leo’s discussion of whether God listens to the prayers of those who make war, suffice to say they are at odds. Vance invites a conversation “I like that the pope is an advocate for peace, I think that’s certainly one of his roles,” said Vice President JD Vance during an appearance at a Turning Point USA event at the University of Georgia this week.

Rather than attacking the pope, Vance said that he likes for the pope to talk about “matters of war and peace” because “at the very least, it invites a conversation.” It is an after-the-fact conversation because rather than make a public case for war and build international support, the US launched attacks on Iran while nuclear talks were ongoing. Vance, a convert to Catholicism, has a book coming out on his faith journey. He also met last year with Pope Leo and said he likes the man.

But, “How can you say that God is never on the side of those who wield the sword?” Vance said at the University of Georgia event. “Was God on the side of the Americans who liberated France from the Nazis? Was God on the side of the Americans who liberated Holocaust camps… ?” Vice President JD Vance speaks during a news conference after meeting with representatives from Pakistan and Iran on Sunday, April 12, 2026, in Islamabad, Pakistan.

Jacquelyn Martin/Pool/AP Vance, in between being heckled by an audience member, added this: “When the pope says that God is never on the side of those who wield the sword — there is more than a thousand-year tradition of just war theory, OK? Now we can of course have disagreements about whether this or that conflict is just, but I think that it’s important in the same way that it’s important for the vice president of the United States to be careful when I talk about matters of public policy, I think it’s very, very important for the pope to be careful when he talks about matters of theology.” Vance has been criticized for the last part of that quote — presuming to tell a pope to be careful about theology — but the comment needs its full context.

It’s also worth noting here that the concept of just war theory has undergone a lot of changes in the intervening thousand years, but it traces back to St. Augustine. Pope Leo comes from the Augustinian order and likely knows a bit about this.

Other Republicans have echoed what Vance said about just war theory. House Speaker Mike Johnson, an evangelical Christian, implied the war on Iran is a “just war.” “It is a very well-settled matter of Christian theology. There’s something called the just war doctrine,” Johnson said.

“There’s a time to every purpose under heaven. I think what the president’s comments, what the vice president’s comments, reflect is their understanding, deep in the SCIF and the classified briefings, of the stakes that are so high in the situation that we’re facing,” Johnson said. House Speaker Mike Johnson walks to the House Chamber at the US Capitol on April 15, 2026.

Graeme Sloan/Sipa USA/AP The US Conference of Catholic Bishops takes a different view of whether the war is just, and it issued a clarification of Pope Leo’s comments Wednesday. “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,” according to the bishops’ statement. The bishops added: “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’ … 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.’” The Trump administration has made a point of distancing the US military from the concept of “defense.” It has added “Department of War” as the secondary name of the Pentagon, changing signs and business cards to lean in to the concept of “warfighting.” Trump and Secretary of Defense Pete Hegseth, who goes by the secondary title of secretary of war, said they made the change to hark back to an era when the US won wars.

So there is something definitely offensive — as in the opposite of defensive — about how they have used the US military. The ‘proportionality’ requirement CNN’s Vatican Correspondent Christopher Lamb wrote about how Leo, the first American pope, has become increasingly vocal about the perils of war. He noted that the Vatican has pointed out that a key principle of just war theory is the idea of “proportionality” — that the destruction caused by military action does not outweigh the good that is intended. Cardinal Blase Cupich, archbishop of Chicago, told CNN’s Ch