Pope Francis is a 'Very Political Person' -Donald Trump

 Imagine this split screen: On one side is Donald Trump, repeating his campaign pledge to build a big wall between the United States and Mexico. On the other is Pope Francis, kneeling to pray for the thousands of undocumented immigrants who have died trying to cross the border.

As the Pope visits Mexico February through February 17, he is not expected to tussle with Trump or directly criticize U.S. immigration policy. Papal aides said Francis wants to avoid appearing to intervene in the presidential election.

That hasn't stopped Trump from taking aim at the Pope.

"I think that the Pope is a very political person. I think that he doesn't understand the problems our country has," Trump said in an interview Thursday on Fox Business. "I don't think he understands the danger of the open border that we have with Mexico."

Will Francis fire back? Not likely. But Catholic leaders say the pontiff will send an unmistakeable message when he travels to the border in Juarez, Mexico next Wednesday.

"He will be calling on us to look with compassion on a group of people who have suffered terribly," said Bishop Mark Seitz of El Paso, Texas, a city that sits across the Rio Grande from Juarez. "And perhaps that will lead people to seek out some different solutions than are now being proposed."

Francis has already spoken out against impenetrable international borders, calling them "monuments of exclusion" and even a "form of suicide" that closes countries in on themselves. He has also urged the United States and Mexico to protect Central American migrants, particularly children, seeking to escape poverty and violence.

It is unclear, though, whether American Catholics are heeding the Pope's message.

Half of Catholics in the United States say they agree with Francis on immigration, according to a survey conducted by the Public Religion Research Institute. But a slight majority (54%) say that Trump, whose signature issue is buttressing the border between the United States and Mexico, would make a "good or great" president, a Pew poll found.

And in a strange bit of statistical symmetry, the exact same percentage of Americans (5%) named the billionaire businessman and famously no-fuss Francis as the man they most admired in 2015, according to Gallup.

But the politics of immigration extend well past the campaign trail.

The Pope's trip to Mexico comes weeks after the Supreme Court -- six of whose justices are Catholics -- agreed to hear a challenge to President Obama's plan to protect millions of undocumented immigrants from deportation. And just last month, the Justice Department announced plans to repatriate some of the 313,000 people who crossed the border illegally last year.

"I don't think the Holy Father's trip to Juarez is political," said the Rev. Timothy Kesicki, president of the U.S.-based Jesuit Conference. "But how could it not have political overtones? It's going to be drawing a lot of attention to immigration at a time when we are having debates about it."

Still, it would be a mistake to view the Pope's Mexican visit solely through an American or political lens, Kesicki and other Catholics said. Mexico is a big, complicated country with far more than immigration and El Norte on its mind.

For his part, Francis told Mexican schoolchildren that he is not coming to their country "as a Magi king" bearing messages, ideas and solutions.

"I am going there to receive the best of you, and to pray with you that the problems of violence, corruption and all that you know is happening can be resolved."

Here are some of the big themes the Pope is expected to address in his five days in Mexico.