Catholic Republicans are developing a pope problem. Earlier this month, Francis recognized Palestinian statehood. This summer, he’s going to issue an encyclical condemning environmental degradation. And in September, just as the GOP primary race heats up, Francis will travel to Washington to address Congress on climate change.

Francis may be popular with the general public, but key Republican primary constituencies — hawks, climate-change skeptics and religious conservatives, including some Catholics, are wary of the pope’s progressivism. Some, pronouncing themselves “Republicans first and Catholics second,” even say they would look askance at a candidate perceived to hew too closely to the bishop of Rome. This internal conflict flips a familiar script, in which Democrats like John Kerry and Joe Biden were labeled “cafeteria Catholics” when their stances on social issues like abortion and gay marriage differed from those of the church.

“In northwest Iowa, we are discussing this a great deal, and sometimes it’s hard for us to reconcile the pronouncements we read from the Holy Father with our conservative principles,” said Sam Clovis, a Catholic and political activist who’s run for U.S. Senate and state treasurer in Iowa.

Jeb Bush — who praised the pontiff in a commencement speech at Liberty University this month — could lose out in the Iowa caucus, said Clovis. “It’s going to cause a lot of problems for Jeb Bush, because Republicans are simply not going to take him seriously,” he said.

Bush declined to address whether his admiration for the pope might affect how religious conservatives view him. In his speech at Liberty he said, “I cannot think of any more subversive moral idea ever loosed on the world than ‘the last shall be first, and the first last.’

“It’s a voice like no other,” he continued, “seen in the example of Francis the saint, or of Francis the pope.”

The other Catholic Republicans in the presidential conversation have taken their own wary approaches to Francis.

Louisiana Gov. Bobby Jindal, who often touts his religious conservatism, has also embraced Francis but sidestepped his apparent differences of opinion with the pope on matters like evolution and the Big Bang. Francis has said that both theories are compatible with Catholicism. But Jindal would not say when asked last year whether the pope’s statement altered his support for a bill that would allow Louisiana schools to teach creationism.

Florida Sen. Marco Rubio and former Pennsylvania Sen. Rick Santorum, meanwhile, have worked to draw a distinction between the pope’s authoritative declarations of Catholic belief, which they would feel compelled to follow, and his mere opinions, which they don’t consider binding. Earlier this month, Rubio said that as a political leader, he had a responsibility to oppose a diplomatic thaw with Cuba, even though the pope had signaled his support for it. In January, Santorum said he was agitated by the pope’s “off the cuff” remarks about Catholics not needing to “breed like rabbits” but that he would continue to heed Francis when “he speaks as the leader of the Catholic Church.” New Jersey Gov. Chris Christie has remained uncharacteristically quiet on Francis, though one of his closest political allies, Catholic billionaire Ken Langone, has complained publicly about the pope’s statements on capitalism and inequality.

As the pope prepares to launch a global lobbying campaign in favor of climate action and a tour of the U.S. that will include an address to Congress made at the invitation of House Speaker John Boehner (R-Ohio), Catholic Republicans have some advice for their fellow Catholics in the GOP field: The candidates can continue to honor Francis’ religious authority while safely disregarding his “political opinion.”

“If I were Jeb Bush, I would say, ‘Look, I don’t think we need to have governmental action to solve this problem. This is a problem, and individuals can make their own decisions to reduce their carbon footprints,’” said conservative Catholic economist Stephen Moore, a fellow at the Heritage Foundation and critic of Francis’ views on climate change and capitalism.

“As a Catholic, you always read what the pope has to say, but this would not have to do with faith and morals,” Rep. Peter King (R-N.Y.) said of Francis’ looming push on climate change. “This would be a political opinion by the pope, or even a scientific opinion. … The pope is no more qualified on that then he is when he says you have to recognize the Palestinians.”

But the distinction between the pope’s moral authority and mere political opinion will get harder to draw this summer when Francis’ forthcoming encyclical is expected to make environmental protection and shielding the poor from the effects of climate change a matter of church doctrine.

“Obviously, when it comes to science, the pope is not infallible. Galileo proved that,” said Thomas Reese, a Jesuit priest and Washington-based analyst for the National Catholic Reporter, though he noted that Francis did earn a master’s degree in chemistry before entering the seminary. “When it comes to, however, the question of the impact of climate change on humanity, this is a moral issue. We’re talking about death and destruction on an apocalyptic scale.”

Reese said the optics of the pope’s congressional address could get awkward. “I think it’s going to be hilarious,” he said. “What’s going to happen when Pope Francis says, ‘You should welcome the immigrants. You should take care of global warming.’ I mean what are the Republicans going to do? Because the Democrats are going to jump and applaud. Are the Republicans just going to sit on their hands?”

Mike McCarron served as executive director of the Florida Conference of Catholic Bishops during Bush’s tenure as governor and Rubio’s tenure as speaker of the Florida House. “It would be my expectation that both of them are going to have a lot of respect for Pope Francis. Both of them regard their Catholic faith very seriously. When I interacted with them, it was very clear that it was important to them.”

And while Rubio has always maintained a respectful tone, he criticized the pope’s support for the U.S.’ diplomatic rapprochement with Cuba, saying in December: “I would also ask His Holiness to take up the cause of freedom and democracy.” “The pope is a shepherd of a faith. … He’s not a political figure,” Rubio said at the Council on Foreign Relations earlier this month. Santorum has been even blunter, remarking in January, “It’s sometimes very difficult to listen to the pope and some of the things he says off the cuff.”

But Bush has praised the pope’s style of public engagement. The former Florida governor told National Review last month that Francis’ attitude could “absolutely” help Catholics in public life. “I do think he can help change the conversation. Because right now, it’s just full of land mines,” said Bush.

Like so much else about Bush, his embrace of Francis places him in sync with a majority of Americans but at odds with large swaths of the Republican primary electorate. Seventy percent of Americans view Francis favorably, as do 90 percent of American Catholics, an approval rating that rivals his now-sainted predecessor John Paul II, according to a February survey by the Pew Research Center.

Clovis, for one, predicts that as Francis becomes more visible in American politics, his fellow conservative Catholics will put party above church. “Rather than being Catholic Republicans, they’re going to be Republicans first and Catholics second,” he said. “If Bush vocally and loudly aligns himself with the pope, that’s a general election strategy, that’s not a primary strategy.”

But for Bush, a devout convert, it may not be a strategy at all. “That’s the thing about Jeb Bush,” said Moore. “This wasn’t a political calculation for him. I think there’s a heartfelt belief that this pope is really spreading Catholic faith around the world.”