As the U.S. presidential campaign exposes contempt for elites and angst over the future, Pope Francis arrives for his first visit with plans to denounce gross inequality and planetary neglect.

The message, delivered by the spiritual leader of 1.2 billion Roman Catholics during a six-day tour starting on September 22, will doubtless focus U.S. public discourse. Francis, 78, has stamped his humble personality on the papacy and has little time for diplomatic niceties.

Having called money “the devil’s dung” when it enslaves people, he seems likely to rattle politicians and business leaders in a country widely seen as the bastion of capitalism.

“The pope says money is OK, capital is OK, but when money becomes a god, an idol, more important than man, that’s not OK - - whatever people in Wall Street think,” said Andrea Tornielli, author of “This Economy Kills,” on Francis’s economic thinking.

From a privileged pulpit -- embracing Congress, the White House, world leaders at the United Nations and about a million faithful at an outdoor mass -- the Argentine pope, the first from the Americas, is expected to condemn what he has called the “globalization of indifference,” especially toward the wave of desperate refugees from the Middle East.

He is slated to give 17 speeches and homilies. The first pope to address a joint session of Congress, he will visit New York and Philadelphia, making pleas for a new world economy and urgent action on climate change.

Francis, who called for “a poor Church for the poor” upon his election in March 2013, will also reach out to the Hispanic community, the homeless and the prison population.

“Excesses of Capitalism"

His message probably will be seized by Bernie Sanders, who is running for the Democratic nomination and has campaigned against the ‘‘billionaire class,’’ as well as businessman Donald Trump, the leading anti-establishment contender in the Republican camp.

Ken Hackett, the U.S. ambassador to the Holy See, predicted that conservatives and liberals will ‘‘pull out the paragraph that fits their agenda,’’ especially ‘‘in the beginnings of a presidential season.’’

He expects the pope to speak about ‘‘the excesses of capitalism,’’ migration and climate change before legislators, he said in an interview in Rome.

‘‘I think that he will call people in our Congress, in our nation, to recapture or capture the values that made our nation great: the hospitality, the generosity, the concern for those who fall through the cracks,’’ Hackett said.

Blames the Markets

Economist Jeffrey Sachs says Francis believes global markets are ‘‘destroying the common good.’’

In the pope’s view, the markets are to blame for human- induced climate change, the trafficking of millions of people, and hundreds of millions of poor people suffering, Sachs -- who works with the Pontifical Academy of Sciences, which advises the pope on economics and the environment -- said via e-mail.

The pope will appeal for ‘‘a new approach to the world economy and society’’ when he meets President Barack Obama and when he speaks to Congress and the UN.

‘He will call for people to overcome what he calls the ‘globalization of indifference’ and instead give help to the excluded, including the poor and the uprooted migrants,’’ said Sachs, who is a professor at Columbia University.

Francis sparked controversy in June, especially in the U.S., when he blamed a ‘‘spiral of self-destruction’’ on rich nations and the global economy in an encyclical, a letter to bishops, titled ‘‘Laudato si,’’ which means ‘‘Praised be.’’

Marxist?

The pope has criticized ‘‘an economy of exclusion and inequality,’’ saying ‘‘such an economy kills.’’ He has spoken of the ‘‘right of control of states’’ to impose limits on the ‘‘absolute autonomy’’ of markets and financial speculation.

Republican candidate Jeb Bush, a Catholic, took offense, remarking, ‘‘I don’t get economic policy from my bishops or my cardinals or my pope.’’ Other conservative critics branded the pope a Marxist.

But the tussle to label the pope is a vain one. Francis is no Marxist and ‘‘is opposed to both the extremes of unfettered markets and the collectivism of communism,’’ Sachs said.

Nor is he an ignoramus; Sachs added he has ‘‘studied deeply and widely’’ and been advised by scientists including many Nobel laureates.

Not that Francis reads economic treatises. ‘‘The pope doesn’t follow any particular school of economics,’’ said Tornielli. ‘‘What inspires him is what he has lived through, including a huge economic crisis in Argentina, and the social doctrine of the church.’’

Obama and Francis

At the White House, Obama and Francis, who will fly in from Cuba, will be ‘‘on the same page’’ on poverty and climate change, Ambassador Hackett said. Francis also is supportive of the Iran deal, he added.

Asked about differences over birth control, abortion and same-sex marriage, Hackett said: ‘‘There are differences. I don’t think that’s where they are going to put all their energies when they sit down one-on-one.”

These issues will feature prominently when Francis attends the World Meeting of Families in Philadelphia, where an estimated million people will attend a mass.

Whatever discord the pope’s visit will prompt, Hackett believes it will be unprecedented because of his pulling power - - dwarfing even presidential inaugurations.

The Secret Service, which is organizing security, “sees this as the biggest event ever,” Hackett said. “This is mammoth.”