Pope Francis has expressed in unusually sharp terms his dismay at “a very strong, organized, reactionary attitude” opposing him within the U.S. Roman Catholic Church, one that fixates on social issues like abortion and sexuality to the exclusion of caring for the poor and the environment.

The pope lamented the “backwardness” of some American conservatives who he said insist on a narrow, outdated and unchanging vision. They refuse, he said, to accept the full breadth of the Church’s mission and the need for changes in doctrine over time.

“I would like to remind these people that backwardness is useless,” Francis, 86, told a group of fellow Jesuits early this month in a meeting at World Youth Day celebrations in Lisbon. “Doing this, you lose the true tradition and you turn to ideologies to have support. In other words, ideologies replace faith.”

His words became public this week, when a transcript of the conversation was published by the Vatican-vetted Jesuit journal La Civiltà Cattolica.

In 2018, in a major document called an apostolic exhortation on the subject of holiness, Francis explicitly wrote that caring for migrants and the poor is as holy a pursuit as opposing abortion. “Our defense of the innocent unborn, for example, needs to be clear, firm and passionate,” he wrote. “Equally sacred, however, are the lives of the poor, those already born, the destitute, the abandoned.”

He has urged priests to welcome and minister to people who are gay, divorced and remarried, and he has called on the whole world to tackle climate change, calling it a moral issue. Francis is set to travel on Thursday to Mongolia for a trip that will highlight interreligious dialogue and the protection of the environment — issues far from the top of the priority list for many American conservatives.

For nearly a decade, Francis’ conservative critics have accused him of leading the church astray and of diluting the faith with a fuzzy pastoral emphasis that blurred — or at times erased — the Church’s traditions and central tenets. Some U.S. bishops have issued public warnings about the Vatican’s direction, with varying degrees of alarm, and clashed with the pope over everything from liturgy and worship styles, to the centrality of abortion opposition in the Catholic faith, to American politics.

In the book, which suggests that the meeting will open a “Pandora’s box” of problems, Cardinal Burke wrote that such from-the-ground-up collaboration leads to “confusion and error and their fruit — indeed schism.”

Bishop Joseph Strickland, who heads a small diocese in East Texas and has become one of the pope’s loudest critics, has accused the pope of undermining the Catholic faith and has invited Francis to fire him. The bishop is under investigation by the Vatican over his leadership of the diocese.

In a public letter released last week, Bishop Strickland warned that many “basic truths” of Catholic teaching would be challenged at the synod, and hinted ominously at an irrevocable break. Those who would “propose changes to that which cannot be changed,” he warned, “are the true schismatics.”

The U.S. Conference of Catholic Bishops backed away from a direct conflict on that issue, after the Vatican warned against using the Eucharist as a political weapon. Francis has preached that communion “is not the reward of saints, but the bread of sinners.”

But some individual bishops have persisted. Archbishop Salvatore J. Cordileone of San Francisco, an outspoken critic of the pope, said last year that Ms. Pelosi would not be permitted to receive communion in his archdiocese unless she was willing to “publicly repudiate” her stance on abortion.

Clashes between the Vatican and conservative American bishops are often amplified and encouraged by conservative media outlets. Popular radio hosts and podcasters regularly question the pope’s leadership and raise questions about his legitimacy. Combative independent websites like Church Militant and LifeSite News cover Francis’ perceived missteps closely, and skewer church institutions they depict as corrupt and profane.

Many of today’s conservative leaders were promoted in the more doctrinaire church of Saint John Paul II and Pope Benedict XVI. They have accused Francis, an Argentine, of being anti-American and anticapitalist, and leading the church away from its core teachings.

Speaking to the Portuguese priests this month, he noted that over the centuries the church had changed its positions on issues like slavery and capital punishment.

“The vision of the doctrine of the church as a monolith is wrong,” he said. “When you go backward, you make something closed off, disconnected from the roots of the church,” eroding morality.

His comments were in response to a question from a Jesuit who said he was taken aback, when he spent a year in the United States, by harsh criticism of the pope from some Catholics, including bishops.

To some people, “the situation of migrants, for example, is a lesser issue,” the pope said. “Some Catholics consider it a secondary issue compared to the ‘grave’ bioethical questions.”

But focusing on issues of sexual morality and downgrading issues of social justice, he said, clashes with his vision of the true church.

“That a politician looking for votes might say such a thing is understandable,” he added. “But not a Christian.”

Francis has steadily thinned out and isolated the most vocal, and in some cases aggressive, American conservative clergy, declining to promote some archbishops to cardinals and so denying them voting rights in the conclave that chooses the pope. In other cases he has simply waited them out and accepted their resignations when they reached mandatory retirement age.

But the American bishops’ conference remains a redoubt of Catholic conservatism, much more conservative than Francis and many of the other national churches.

On a flight to Africa in 2019, Francis seemed to acknowledge a well-financed and media-backed American effort to undermine his pontificate, saying it was an “an honor that the Americans attack me” when asked about the American conservative-media complex.

On the return flight, he was asked about the sustained opposition from Catholic conservatives in the United States who had accused him of driving traditionalists to break with the church. Francis said he hoped it didn’t come to that, but wasn’t necessarily terrified at the prospect either.

“I pray there are no schisms,” Francis said at the time. “But I’m not scared.”