Open this photo in gallery:

Prime Minister Mark Carney, left, U.S. President Donald Trump, centre, and U.S. Vice-President JD Vance in the Oval Office of the White House on Tuesday.Anna Moneymaker/Getty Images

When Mark Carney went to dinner at U.S. Vice-President JD Vance’s home during the Prime Minister’s trip to Washington this week, it wasn’t the first time the pair had sat down for their own tête-à-tête.

In Rome this spring, they met on the margins of the inaugural mass for Pope Leo XIV.

That event was one of not just diplomatic importance for the two men, but of personal significance: They are both practising Catholics. Mr. Carney was raised in the faith, and Mr. Vance converted to it in 2019.

Their shared faith – and their public commitment to it – creates the potential for dinner-table conversation unlike what might transpire with other world leaders, said Brian Dijkema, the president of Canada at Cardus, a think tank whose work is informed by Christian theology.

Opinion: Donald Trump is expanding his list of political enemies. It’s ‘us’ vs. ‘them’

“I would have loved to have known whether they discussed the implications of their theology for their political lives,” he said in an interview.

“I think they would have arrived at very different spots.”

Neither the Prime Minister’s Office nor Mr. Vance’s provided any further details of the pair’s dinner Tuesday or how it came to be.

While little may be known about what was on the table, Mr. Vance did share the menu: salad, salmon and a dessert made by what he described as the “world’s youngest pastry chef,” his daughter, Mirabel. It was called “Miramisu.”

A readout from Mr. Carney’s office said they discussed “common priorities and the broader work to build a new economic and security relationship.”

Their dinner followed the meeting earlier in the day between Mr. Carney and U.S. President Donald Trump, where discussions centred around progress toward a new trade deal.

Opinion: After Trump visit, Poilievre blames Carney for everything under the sun, including sunburn

Historian J.D.M. Stewart, who has written extensively on Canada’s prime ministers, said that given the high stakes in the Canada-U.S. relationship, it makes perfect sense for the two men to engage.

Precedent shows that a relationship at that level can pay dividends; former prime minister Brian Mulroney once gave then-U.S. vice-president George H.W. Bush “an earful” on acid rain, and the two countries would soon sign a cross-border treaty on the subject.

That Mr. Carney and Mr. Vance met in Rome does provide a common point of interest, Mr. Stewart said.

“And when two people have common points of interest, that’s a nice thing to start with. I don’t know how much importance I would put on it, but I wouldn’t dismiss it either.”

On trade, religious teachings could guide the discussion, said Mr. Dijkema, noting a long Christian tradition of thought on work and the economy, including concerns about the plight of the working class.

In an essay explaining his conversion to Catholicism, Mr. Vance cites being drawn to it because it is “sympathetic with the meek and poor of the world without treating them primarily as victims.”

Open this photo in gallery:

Mr. Vance converted to Catholicism in 2019 and has previously tried to use theology to justify his government’s actions.Evan Vucci/The Associated Press

Mr. Carney, meanwhile, has pointed to lessons from Pope Francis informing his economic philosophy, though in Rome this past spring, he played down a direct linkage between his religion and how he’ll govern.

The only influence his Catholicism has on his political life is the fact that he’s in politics at all, he told reporters.

“I feel because of that, responsibility, a sense of service, which is one of the reasons why I put myself forward. It does not have an influence on the policies the government follows.”

Mr. Vance has explicitly attempted to use theology to justify his government’s actions.

In February, for example, he invoked the Catholic ideal of ordo amoris – that people owe duties of care first to the people closest to them – to justify the Trump administration’s mass deportations, leading to criticism from Pope Francis and Catholic theologians, who said he had misunderstood the concept.

Rocco Palmo, a Philadelphia-based Catholic writer and commentator, pointed to Mr. Carney’s life-long Catholicism compared with Mr. Vance’s coming to the church as an adult as a point of differentiation that could explain the Prime Minister’s more low-key approach to his faith.

“You have to weigh the difference between a cultural Catholicism that you’re born into and a convert Catholicism or political Catholicism,” he said.

Mr. Palmo said the U.S. deportation agenda is causing deep unease among some American Catholics in part for historical reasons: During the mid-19th century, it was Catholics who were the target of the nativist Know Nothing Party, so Mr. Vance’s alignment with a nativist agenda hits home.

Opinion: The deplorable rise of MAGA Catholicism

“Among many American bishops, the question is ‘have we returned to the era of the Know Nothings in terms of immigration and are the Know Nothings our own people?’ ”

Mr. Vance has also cited being drawn to Catholicism because it aligns with his own socially conservative views; Mr. Carney, by contrast, has faced criticism from other Catholics because his social views aren’t seen as aligned with his faith.

“I would say that someone who is in politics and claims to be living according to their faith and making such statements, we see the disconnect, and this is unfortunate with many of our politicians,” William McGrattan, the president of the Canadian Conference of Catholic Bishops, said earlier in the year on the subject of Mr. Carney’s support for a woman’s right to choose an abortion.

The extent to which either man is actually practising politics in accordance with their faith could come down to a singular question, said Mr. Dijekma: Would they quit politics for it?

“When I’m looking at the willingness of people to take their faith seriously in the public square, where is that point at which you’re willing to say, ‘I’m going to exchange power in return for maintaining fidelity to what I believe to be true?’”