VATICAN CITY —
Oh, to be a fly on the wall.
When Pope Francis meets with President Donald Trump at the Vatican at the end of this month, the world will be watching how the Argentine "slum pope'' interacts with the brash, New York billionaire-turned-president.
On many issues and priorities, the two men couldn't be more different. Francis wants bridges between nations, not the walls Trump is building. Francis brought back a dozen Muslim Syrian refugees with him when he went to Greece last year, while Trump has tried to impose a travel ban on people from a half-dozen mostly Muslim nations.
The pope sleeps in a two-room hotel suite. Trump lived in a skyscraper with his name on it before being elected.
Francis wants to end the use of fossil fuels, while Trump has pledged to cancel payments to U.N. climate change programs and pull out of the Paris climate accord. U.S. bishops have praised the Trump administration for its anti-abortion stance, but have opposed Republican health care plans because of their impact on the poor.
Those issues and more are likely on the table when Trump arrives May 24 at the Apostolic Palace in Rome for the 8:30 a.m. audience that was announced Thursday.
Despite their obvious differences, Trump and Francis share a populist bent. Both were elected on reform mandates and speak with a simplicity that has endeared them to their bases. And both share a common concern about the plight of Christians in the Middle East at the hands of Islamic militants.
"They're both populists, but populists of a different kind,'' said Mathew Schmalz, associate professor of religious studies at The College of the Holy Cross in Worcester, Massachusetts. While agreeing they are both concerned about Islamic extremism, he said they differ in approaches and vision.
"I'm not sure the Vatican at this stage wants to play along with the role envisioned by ... Catholic advisers of Donald Trump, who want to resurrect the imagery of a civilizational conflict between Christianity and Islam,'' he said.
Yet in announcing his first foreign trip itinerary Thursday, which includes stops in Saudi Arabia and Israel, Trump said he chose Saudi Arabia as his first stop precisely because it's the home of two of the holiest sites in Islam. He said he wanted to "begin to construct a new foundation of cooperation and support with our Muslim allies to combat extremism, terrorism and violence and to embrace a more just and hopeful future for young Muslims in their countries.''
The thrice-married Trump was raised as a Presbyterian and described himself as a "religious person'' during his campaign, but often struggled to affirm his Christian credentials as he wooed the Evangelical voters who helped elect him.
Francis hasn't commented on Trump's presidency other than to say, on the day of his inauguration, that he'd take a wait-and-see approach. But Francis has railed against the "false forms of security'' promised by populist leaders who want to wall themselves off and has called for world leaders to seek a future of greater solidarity.
The two got off to a rocky start when, during the U.S. presidential campaign, Francis said anyone who wants to build a wall to keep out foreigners is "not Christian.'' Trump, who campaigned on plans to build a wall on the U.S. border with Mexico, shot back, saying it was "disgraceful'' for a religious leader to question someone's faith.
More recently, Francis has urged the U.S. and North Korea to step away from the brink and use negotiations and diplomacy to defuse tensions on the Korean peninsula.
Francis also wrote an entire encyclical about the environment and the moral imperative to save God's creation, denouncing how the wealthy had destroyed the Earth at the expense of the poor. At the end of the audience, he will most certainly hand over a copy of "Praise Be'' to Trump, who has sought to get rid of regulations he feels are burdensome to business.
Dennis Doyle, a professor of religious studies at the University of Dayton, said both men are seen by their supporters as having an authenticity that shakes up the status quo. But beyond that, there's not much in common, he said.
"I really don't see a lot of middle ground here,'' he said.
The Vatican and the White House have often had different views over the years. During the previous two papacies, divisive issues like abortion and homosexuality often defined relations between the White House and the U.S. Conference of Catholic Bishops — which then carried over to U.S.-Holy See relations.
But the two always found ways to collaborate, promoting initiatives to fight human trafficking and working to bridge the U.S. detente with Cuba.
U.S. bishops did strongly challenge the Obama administration's health care mandate requiring insurance coverage for birth control. Trump on Thursday signed an executive order promising "regulatory relief'' for groups with religious objections to the requirement.