WASHINGTON — Expect to hear the pope take on immigration, hunger and the environment when he visits in September, said three policy advisers helping reporters in Washington prepare for the pontiff’s upcoming visit.

“This is a pope that doesn’t hesitate to enter difficult areas and waters,” said Demetrios Papademetriou. president emeritus of the Migration Policy Institute, a Washington think tank, and one of three panelists at a briefing on “Covering the Pope: Policy and Politics.”

These “happen to be three of the most contentious, most debated, stickiest issues that Capitol Hill and the country have dealt with in the last … several decades,” said Jason Dick, an editor at CQ Roll Call, who moderated the Aug. 3 panel at Washington’s Woodrow Wilson International Center for Scholars.

Pope Francis will speak “in a very clear way” about issues “that lots of people will want to hear” him address, said Papademetriou, a former senior policy adviser on immigration and refugee issues to the U.S. Catholic bishops. Particularly, he will talk about what some call “illegal” immigration but “he’ll call it undocumented, unauthorized, unregulated” mass migration, Papademetriou said.

“It’s not about all immigration, it’s about immigration of the poor, immigration of the persecuted, immigration of the people who seemingly have no other choice but to go elsewhere in order to create a life for themselves,” Papademetriou said.

And his focus will be on issues of protection of people, mainly refugees and temporarily protected people.

“These have always been the foci of the (Catholic) church’s concern with migration,” Papademetriou said. “The church … they argue for protection, for saving lives, for treating people properly, for not taking advantage, and exploiting people, (the church) argues strongly against discrimination.”

Yet when it comes to this topic, Papademetriou said, “I’m not quite sure whether the U.S. Congress, or at least those people in the U.S. Congress, who have been unable or unwilling to reach any agreement … that it will influence them in one way or another.”

Panelist Lisa Marsh Ryerson, president of AARP Foundation, said the papal visit will help shine a light on a key issue for the pope, namely hunger, which affects the poor in the United States

“He speaks on many occasions about dignity for all people,” she said. And when the pope brings up the topic of hunger, it will help ask and answer questions such as: “Why, in a land of such abundance, where we are producing food, do we have such a persistent disconnect between the food supply chain and those who are hungry?”

Kalee Kreider, policy adviser for climate science at the United Nations Foundation, said the three issues — hunger, the environment and immigration — are connected and encouraged reporters for secular news organizations to read “Laudato Si’, on Care for Our Common Home” to get a taste of the case the pope will make and how he touches on the three topics.

“The pope makes clear that poverty, climate change are not two different things,” said Kreider, a former environmental adviser and communications director for Vice President Al Gore.

These issues, she said, have been addressed by the Catholic Church and by previous popes for decades. But Pope Francis’ encyclical hits a particular time, a “tipping point,” that history will recall, she said.

She described it as part of an “arc” that began Aug. 3, when U.S. President Barack Obama unveiled the “Clean Power Plan,” a pledge by his administration to reduce the country’s carbon dioxide emissions and combat climate change. It continues with the pope’s message on the environment during his visit to the United States in September and whose influence may result, as environmentalists hope, in some form of global action during the U.N. Climate Change Conference in Paris in late 2015.

History will ask whether given the force behind the three events — a major world power promising to curb CO2 emissions, a major faith leader calling for better care of the earth by humans, and the meeting of international leaders agreeing on worldwide reduction of greenhouse gases — humanity was able to take urgent action on climate change, Kreider said.

She said she shared the sentiment of panelist Papademetriou: “I agree that the pope’s influence will largely be on the broader public,” and not on politicians who will make decisions for the country, she said. But sometimes it takes the public’s sentiment to influence change carried out by Congress and the influence of the pontiff’s visit and its message may not be seen until next year, she said.

“What will be intriguing, to me,” she said, “is whether we do see a softening on some of these flashpoint issues. … It won’t be until general election that we’ll actually start to see (the) impact of a visit like this.”

While August in Washington tends to be a sleepy time, with Congress recessed and denizens on summer vacation, the pope’s September visit has made this a month of preparation, of reading encyclicals, studying the pope’s speeches, and, for some, brushing up on their Spanish-language skills since the pontiff is expected to make many of his speeches in his native tongue.

More than 7,000 individuals and 600 organizations have applied for credentials or space to cover events for Pope Francis’ U.S. visit — even as his approval numbers are down.

Last year, 76 percent viewed the pope favorably, according to a Gallup poll, compared to 59 percent this year.

“One could argue that this decline is probably based on his encyclical and a bit about his message about poverty,” said William Douglas, congressional correspondent for McClatchy Newspapers.

But the pope is intent on getting his message across, said Papademetriou, no matter how uncomfortable it may be for some.

“He expects people to engage,” he said. “He wants to force people to engage those big issues from a far broader perspective that goes well beyond Catholic teaching, as it were.”