When Stuart Sepulvida arrives at St. Francis de Sales Roman Catholic Parish in Tucson, Ariz., for Mass, which he attends most mornings, he passes a display honoring local soldiers and encouraging parishioners to pray for their safety. Hundreds of small cards record their names: Robles, Arenas, Grajeda. A portrait of Pope Leo XIV hangs across the lobby.

Mr. Sepulvida, 81, is a Vietnam veteran whose patriotism and Catholicism are deeply intertwined. He voted for President Trump three times but has never felt more betrayed by an American president than when Mr. Trump denounced Pope Leo as “weak on crime” and “terrible for foreign policy.”

“It was very disturbing to me to hear both of them clashing like they did,” Mr. Sepulvida said, standing outside the church one morning this week. Now, he is reconsidering whether he will vote Republican this year.

The Republican Party is struggling to hold onto the support from Hispanic voters who helped propel Mr. Trump back into the White House in 2024. Yet as many party leaders have acknowledged the urgent need to stop the backsliding among Latinos, the president has enraged many of even his strongest supporters by clashing with the pope.

On Easter Sunday, Pope Leo, the first U.S.-born pontiff, spoke of the need to “abandon every desire for conflict, domination and power, and implore the Lord to grant his peace to a world ravaged by wars.” Within days, Mr. Trump, who has led the United States into a war with Iran, said the pope was “catering to the radical left” and posted an AI-generated image portraying himself as a Jesus figure. Mr. Trump later deleted the image, saying he thought it depicted him as a doctor.

“It just isn’t what a president should do,” Mr. Sepulvida said. “The pope speaks for his people. He is beyond politics.”

Mr. Trump won 55 percent of Catholic voters in the 2024 election, compared to 43 percent who voted for former Vice President Kamala Harris, according to Pew Research Center. The most sizable gains came from Hispanic Catholics. While Joseph R. Biden Jr. won their votes by a 35-point margin in 2020, the Democratic advantage shrunk to 17 points in 2024. Now, just 18 percent of Hispanic Catholics said they support most or all of President Trump’s agenda, according to a poll from Pew released earlier this year.

If the president’s quarrel with the pope sours more Latinos on the Republican Party, it could affect midterm races across the country, including in South Florida and South Texas, where Republicans have notched important victories in predominantly Hispanic districts in recent years.

In Arizona’s Sixth Congressional District, which stretches from north of Tucson to the Mexican border, voters were still grappling with the fallout this week.

The district is roughly evenly divided among Republicans, Democrats and independent voters. Nearly a third of the district is Hispanic, and there is a significant population of members of the Church of Jesus Christ of Latter-day Saints, as well as a large Catholic community with deep history in the region. It also has one of largest numbers of military veterans of all congressional districts in the country.

“The president is looking for a lot of attention from everything,” said Maria Ramos, 60, who regularly attends weekday Mass at St. Francis. A registered independent, she usually votes for Democrats but often declines to cast a ballot if she views a candidate as too liberal. “He believes he can put God in his place. He’s meddling in countries that he’s not in control of — he wants to control the world.”

“It is not just a very serious lack of respect — it is a mortal sin,” she said, shaking her head. One word comes to her mind again and again, she said: disgust.

Like so many others in southern Arizona, Ms. Ramos has several relatives who serve in the military — a path they saw to both serve the country and as an entry into the stable middle class. Many of them, she said, voted for Mr. Trump for president.

The Tucson district is now widely seen as one of the most competitive in the country. Republican Juan Ciscomani narrowly won the district in 2022, in part by emphasizing his biography as a Mexican immigrant and a devoted father of six children. He is also an evangelical Christian, a group that has driven much of the growth among Hispanic Republican voters in recent years.

Mr. Ciscomani declined a request for an interview, but when a local radio host asked Mr. Ciscomani what he thought of Mr. Trump’s comments “as a man of faith,” the congressman declined to criticize the president but said, “You can trust that you won’t see any meme like that coming out of my account.”

JoAnna Mendoza, the Democrat challenging Mr. Ciscomani this fall, has made her 20-year career in the U.S. Navy and Marines a key aspect of her story on the campaign trail. While she rarely speaks about her religious background and no longer considers herself a practicing Catholic, she said she briefly considered becoming a nun as a teenager. She criticized Mr. Ciscomani for not condemning the president’s remarks.

“You can’t make faith a central part of your campaign and then allow this to stand,” she said in an interview.

Across Tucson, Latino Catholics, regardless of their past voting preferences, were similarly quick to condemn the president’s remarks.

When Cecilia Taisipic, 71, heard about it, she said, she winced with shame about her vote for him in 2024.

“I thought he would make the country better, but apparently it’s the opposite,” she said as she left Mass at St. Francis earlier this week. She is so fed up with politics, she said, that she is unlikely to vote at all this year. “When it comes to my faith, I don’t like anybody to challenge it. Now I don’t want to hear anything on the news. I just want to pray.”

Matilde Robinson Bours, 63, teaches a weekly Spanish Bible study class at St. Thomas the Apostle Parish, and like nearly all of the women in her class, she immigrated from Mexico decades ago. She has voted for Republicans in nearly every election since she became a citizen. Though she has never liked President Trump, she said, his comments about the pope enraged her more than anything else he has said or done in the past.

“This surpassed everything, every social and political norm — this is personal to all Catholics,” she said. “The arrogance and ego is disgusting. To think that he is God? The pope has every right and responsibility to talk about peace.”

Still, Ms. Robinson Bours said, nothing will stop her from supporting Republicans again this year. She has been delighted that her adult children have stopped supporting Democrats in recent elections.

“Almost everyone I know thinks the way I do,” she said.

Patricia Martinez, 86, who has attended the same Bible study as Ms. Robinson Bours for years, shook her head in disagreement. She said she cannot imagine voting for a Republican who supports Mr. Trump.

“This is different — this shows he is out of his mind,” said Ms. Martinez. “We have to have basic respect and teach that to people in this country.”

Patrick Robles, a 24-year-old native of Tucson, spent years alienated from the Roman Catholic Church, but returned to his faith more recently. “The craziness of the world sort of caused me to seek some sort of answers,” he said. Now, he attends Mass at the St. Augustine Cathedral in downtown Tucson, a few blocks from the office where he works as an aide to Representative Adelita Grijalva, a Democrat.

Mr. Robles said he saw Mr. Trump’s battle with the pope as both a personal affront and a political opportunity.

“The president is basically trying to draw a line between Catholics and what we perceive to be patriotism,” he said. “I believe we can be both.”

Last week, he texted one of his uncles who has supported Mr. Trump in every election asking him what he thought.

“I’m afraid we need divine intervention,” the uncle replied.