Donald Trump’s depiction of himself as Jesus Christ and recent spat with Pope Leo XIV could come back to bite him and the Republican party in the midterm elections, according to experts, with some newly aggrieved Christian groups set to play an outsized role in key races across the US.

The president’s Trump-as-the-Messiah Truth Social post sparked immediate criticism among some Christians, including some on the right. Trump, 79, said he thought the AI image of him administering an ethereal light to a stricken man’s head as translucent figures descended from the heavens represented him as a doctor.

“Blasphemous,” was the verdict of Douglas Wilson, a self-described Christian nationalist who believes women should not be able to vote, and a confidant of Pete Hegseth, the US defense secretary.

“This should be deleted immediately. There’s no context where this is acceptable,” Sean Feucht, a Christian activist who is partnering with the Trump administration on a “Worship Tour”, posted on social media.

Trump’s post was ultimately taken down, although the level of his apology was brought into question when he then posted an AI image of what appeared to be Jesus Christ cuddling him.

“He did seem to cross a line for some of his Christian supporters,” said Kristin Kobes Du Mez, a professor at Calvin University and an expert on white American evangelicals. She noted that Trump’s supporters have been prepared to put up with plenty of other things.

“Really, from day one, with him bragging on camera that he assaulted women in the Access Hollywood tape to, even just very recently, threatening to annihilate an entire civilization. He is also detaining children, and there are allegations right now related to the Epstein files.

“There is a lot out there that arguably should concern Christian supporters, and the fact that it was this AI-generated image that sparked this outcry is worth pondering. I think it felt like it crossed the line for some because it was just so blatant.”

Yet Du Mez said not all the outrage may have been sincere.

“I sense that there was this kind of performative aspect that enough Christian leaders knew that they needed to be on record saying: ‘We don’t approve of this. But again, that’s something very different from them actually withdrawing their support from him,” she said.

Feucht, the Worship Tour guru, certainly got over it quickly. Within hours he had uncritically reposted Trump’s “doctor” explanation. Riley Gaines, a Christian, anti-trans activist, initially responded to the Trump image: “A little humility would serve him well.” Later that day, Gaines wrote on social media: “I love the President and I’m so grateful he’s in the Oval Office.”

Robert Jones, president and founder of the Public Religion Research Institute (PRRI), said Trump’s support among white evangelicals and Christian nationalists would probably endure.

“They’re just more conservative than Catholics are. They’re heavily concentrated in the south, so they come out of this kind of southern US history, and they’re frankly more motivated by racism. So the anti-immigrant, anti-Islam drumbeat is kind of fuelling the Maga movement. And the flip side of that anti-Islam, anti-immigrant drumbeat is [the right wing’s] positive vision of a white Christian America.”

Trump’s attacks on Pope Leo – the president has called him “wrong on the issues” and, bizarrely, “weak on crime” – also may not be important to that white evangelical base: some have even backed Trump’s attacks on the pontiff. But those Christians are likely to be less important than others in this year’s elections.

“White evangelicals, except for maybe in Georgia and North Carolina, aren’t actually going to help the Republican party in the midterms that much, because most they’re mostly concentrated in fairly safe, red states and red districts. They’re heavily concentrated in the south, where Republicans are going to win anyway,” Jones said.

“If you ask, though, who are the biggest religious groups in the more competitive states and districts, the answer is Catholics.”

White Catholics, in particular, could have a big say in the midterms, PRRI data shows. A majority of them voted for Trump in 2024 – Hispanic Catholics tended to support Harris – meaning a loss in their support could influence competitive races.

And unfortunately for the Republican party, white Catholics are overrepresented in several swing states, where there are seats which fluctuate between Republican and Democrat. White Catholics make up 12% of the nation as a whole, according to PRRI, but in Pennsylvania they make up 18% of the population; in Wisconsin 22%, and they overindex in Michigan, too.

“In these more competitive districts and swing states, if he loses 10 points among white evangelicals, he and Republicans might be able to weather that. If they lose 10 points among white Catholics, that’s going to be game over in many elections in the midterms,” Jones said.