When he visits Mexico in mid-February, Pope Francis, who has made the plight of migrants one of the central themes of his papacy, should have no mercy with Republican hopeful Donald Trump.

Francis will have a unique opportunity to expose Trump as a pathological liar on immigration matters, just after the key Republican primary in New Hampshire, when most Americans will begin to seriously tune into the race for the U.S. November elections. It will be Francis’ best opportunity to have a real impact on the immigration debate.

I will probably never get a job as a papal speechwriter, but if I were on Francis’ team, this is what I would suggest he say during his scheduled Feb. 17 visit to the Mexico-U.S. border city of Ciudad Juarez, where he is widely expected to address the immigration issue. Here it goes:

“I greet all of you with special affection!” he should start saying. “As you know, migrants have always been very close to my heart. I come from a country of European migrants, who moved to this continent in search of building new lives, leaving behind wars and economic hardships. My own father was a migrant.

“As we have said since my first official trip abroad when I visited Lampedusa, Sicily, to commemorate the thousands of migrants who died trying to cross the sea from North Africa, we must fight against the globalization of indifference. We have become used to other people’s suffering. We don’t care.

“What’s worse, people running for top political offices in some of the world’s richest countries are using the immigration issue as a demagogic tool to frighten people. They cite false figures to inject fear in their countries’ populations, and to present themselves as saviors of the fatherland.

“There are some of these fear-mongering presidential hopefuls who promise to erect walls along the borders to stop an alleged invasion of migrants, when the truth is that the flow of migrants has gone down sharply in their countries.

“These fear-mongers incite crowds with proposals to deport millions of undocumented workers, most of whom are law-abiding citizens who contribute to their adopted countries’ economy. Their families would be divided by mass deportations. Children would be separated from their parents.

“These demagogues try to dehumanize undocumented migrants by calling them ‘illegals,’ as if they were objects, rather than human beings who deserve our Christian love.

“Dear friends, in this very place, the crossroads of two great nations, let us state that you cannot claim to be a good Christian while advocating for policies that are based on false premises, and that would cause great human suffering.”

If Francis makes a speech along those lines, many Americans may become interested in learning more about immigration, and would realize the extent to which Trump — and most other Republican hopefuls, for that matter — are misleading the public.

For instance, Francis’ statements would draw attention on a recent Pew Research Center study showing that immigration in the United States has actually dropped in recent years. Today’s estimated 11 million undocumented residents make up 3.5 percent of the U.S. population, down from 4 percent in 2007, the study said.

What’s more, contrary to Trump’s claims that there is an avalanche of Mexican migrants, the Pew Research study cites U.S. and Mexican government data showing that there is a reverse migration going on: one million Mexicans left from the United States to Mexico over the past five years, whereas 870,000 Mexicans crossed the border into the United States.

And a wall along the 2,000-mile U.S.-Mexico border would not only cost billions of dollars, but would be a waste of time and money: Up to 45 percent of the undocumented migrants don’t enter the country through the border, but fly in by plane and overstay their visas, according to a previous Pew Research Center study.

My opinion: During his visit to Mexico, Francis should not mince words to denounce Trump’s misleading anti-immigrant rhetoric. While the pope, true to Vatican style, will probably not name any presidential hopeful by name, he should come as close as he can to single out Trump’s racist demagoguery.

— Andres Oppenheimer is a Latin America correspondent for the Miami Herald.