Dublin • Pope Francis has long faced criticism from traditionalists — a group that includes academics as well as cardinals — who say the church is too willingly following the whims of the anything-goes modern age.

Much of the dissent has remained within the Vatican’s walls as Francis’ opponents worked to stonewall reforms. A few high-ranking church leaders have questioned him publicly about his teachings. But the simmering opposition has suddenly exploded across the Catholic world, with a former Vatican ambassador accusing the pope of covering up sexual abuse — and demanding that Francis step down.

The accusations came in a 7,000-word letter written by Archbishop Carlo Maria Viganò that could be viewed as an act of courage or unprecedented defiance. Either way, it sheds light on the opposition movement, and particularly its insistence that homosexuality within the church — and Francis’ inability to keep it at bay — is to blame for the sexual abuse crisis.

Defenders of the pope note that the letter was published at perhaps the most challenging point of Francis’ papacy, when abuse scandals in the United States, Chile, Australia and elsewhere are embroiling members of the church hierarchy.

“We are a step away from schism,” said Michael Sean Winters, a columnist for the National Catholic Reporter. “I think there is a perception among the pope’s critics that there is vulnerability here — on the part of the pope and in the Vatican generally.”

The document alleges that Francis, as well as predecessor Pope Benedict XVI, had known for years about abuse allegations against Theodore McCarrick, who last month became the first cardinal in nearly a century to resign. Francis, asked about the accusations on Sunday, did not directly respond to them, saying that the document “speaks for itself.”

The author, Viganò, a 77-year-old who is two years into retirement, is described by acquaintances as shy and quiet, but he has a history of advocating for right-wing causes. During the pope’s U.S. visit in 2015, he orchestrated a meeting between Francis and a conservative county clerk who defied a federal order to issue same-sex marriage licenses. In Italy this year, he spoke briefly at a gathering of dissenters that included Cardinal Raymond Burke, perhaps the most prominent anti-Francis figure.

“All of the traditionalist outlets have given Viganò’s letter a great echo, because that was the voice that they were waiting for,” said Roberto de Mattei, president of the conservative Lepanto Foundation and a critic of Francis. “At last a bishop has spoken. This explains the consensus from the world of critics. Viganò was not a leader [of the group]. But he joined critical voices that already existed.”

Francis has used more inclusive messages about gays and divorced Catholics at a time when the religion is losing its hold across the Western world. But some conservatives feel that Francis — who has made no concrete changes to church teaching on homosexuality or the role of women in the church — risks undoing the credibility of a religion that is based on immutable ideas and principles.

In the letter, Viganò goes into detail about years of failures to act within the Vatican bureaucracy, and he describes “dismay and sadness over the enormity of what is happening.” He mentions “homosexual networks” within the church and quotes an academic who cites such networks as a core reason for clergy abuse.

“The seriousness of homosexual behavior must be denounced,” Viganò wrote.

With his letter, Viganò became the torchbearer for the argument, shared among a group of Catholic conservatives, that sexual abuse stems from an overabundance of priests with homosexual feelings. They charge that Francis, who describes abuse in terms of power and clerical narcissism, fundamentally misunderstands the issue, jeopardizing the church’s ability to address the scandals.

In an interview published Monday by the conservative Italian newspaper La Verità, Burke said that “homosexual culture” had found “roots inside the church and can be connected to the drama of abuses perpetrated on adolescents and young adults.”

That view has little hold in the mainstream and has been roundly dismissed by researchers and other outsiders, who say that sexual abuse results from a complicated combination of factors including church secrecy, the training and sexual development of young priests, and the profound power gap between clergy and young parishioners. Those who want to see dramatic change in the church sometimes criticize the requirement for celibacy. Scores of girls have also been victimized, though less frequently than boys.

“A lot of this is homophobia,” said Father James Martin, an American Jesuit who has advocated for the church to welcome LGBT members with more compassion. “I think they’re using abuse to beat up on gays.”

For traditionalists, Martin’s invitation from the Vatican to speak last week in Dublin at a massive World Meeting of Families event was proof of how Francis is gradually eroding church teachings on sexuality. Before Francis landed in Dublin, a group of 400 dissidents met for two days at a hotel for what one organizer called a gathering to promote “the authentic teachings of the Catholic Church.” And in Madison, Wisc., responding to the church’s sex abuse crisis, Bishop Robert Morlino wrote in a letter to Catholics in his diocese that “it is time to admit that there is a homosexual subculture within the hierarchy of the Catholic Church.”

Last week, Francis had released a letter to Catholics acknowledging “crimes” committed by the church. LifeSiteNews said the letter was facing criticism from “faithful Catholics” for “ignoring the underlying issue of rampant homosexuality in the clergy.” LifeSiteNews was one of the two conservative outlets that initially published Viganò’s letter.

Though Francis did not directly address the claims in the letter, he delivered a message Sunday night to reporters on the papal plane that seemed ready-made to roil his critics. Asked by a reporter what a parent should say to a child who comes out as gay, the pope said: “Don’t condemn. Dialogue, understand.”

“I’ll never say that silence is a remedy,” Francis said. “To ignore a son or daughter with homosexual tendencies is a lack of paternity and maternity. You are my son, you are my daughter as you are! I’m your father, mother. Let’s talk!”