Pope Francis greets a crowd on his way to a meeting with cardinals at the Vatican on Feb. 21, 2014. RNS photo by David Gibson

(RNS) Of all the events and appearances and celebrations on Pope Francis’ schedule for his Sept. 22-27 visit to the U.S., none has prompted as much speculation as his Thursday morning address to a joint meeting of the House and Senate.

It will mark the first time a Roman pontiff has addressed Congress, and given the intense political reactions to Francis’ many pointed remarks have evoked (at least one congressman, a Catholic, will boycott the talk over the pope’s views on global warming), everyone is keen to see what Francis will say, and how it will play.

Even those close to the pope say they aren’t sure what to expect.

But one well-connected Italian Vatican-watcher, Andrea Gagliarducci, says he has spoken with a Vatican official who has seen early drafts of the speech and in a story at Catholic News Agency he says Francis will focus on two issues: economics and immigration.

According to the source, the speech will seek to clarify Francis’ criticisms of global capitalism:

“Pope Francis will clarify that he never said he wants to abolish the market, but that he said the market needs a purification,” Gagliarducci reports.

His source also said immigration is “likely be a core issue” in the papal speech to Congress, “with the Pope praising the United States for their multicultural composition, while also calling for a wider welcoming of immigrants.”

“Pope Francis has already given a sign of what he would like the U.S. to do in terms of immigration. When he took part to the ABC show 20/20, he directly addressed Sr. Norma Pimentel, the director of Catholic Charities in Rio Grande, who manages a welcoming center for immigrants who are left at the border. That’s the kind of welcoming he thinks about,” the source maintained.

CNA is a conservative outlet whose correspondents — including Gagliarducci — have often been critical of Francis. It’s notable that CNA’s source did not mention abortion or gay marriage or religious freedom as themes of the address to Congress.

Those issues will certainly come up during the visit, but where they come up, and how the pope raises them, will have a big impact on their political ramifications during a presidential campaign that has gotten a head start on intensity, to say the least.

END GIBSON