U.S. nuns are preparing to assemble in St. Louis this week for a pivotal meeting at which they will try to decide how to respond to a scathing critique of their doctrinal loyalty issued this spring by the Vatican — a report that has prompted Roman Catholics across the country to rally to the nuns’ defense.

The nuns will be weighing whether to cooperate with the three bishops appointed by the Vatican to supervise the overhaul of their organization, the Leadership Conference of Women Religious, which represents about 80 percent of women’s Catholic religious orders in the United States.

The Leadership Conference says it is considering at least six options that range from submitting graciously to the takeover to forming a new organization independent of Vatican control, as well other possible courses of action that lie between those poles.

What is in essence a power struggle between the nuns and the church’s hierarchy had been building for decades, church scholars say. At issue are questions of obedience and autonomy, what it means to be a faithful Catholic and different understandings of the Second Vatican Council.

Sister Pat Farrell, the president of the Leadership Conference, said in an interview that the Vatican seems to regard questioning as defiance, while the sisters see it as a form of faithfulness.

“We have a differing perspective on obedience,” Farrell said. “Our understanding is that we need to continue to respond to the signs of the times, and the new questions and issues that arise in the complexities of modern life are not something we see as a threat.”

These same conflicts are gripping the Catholic Church at large. Nearly 50 years after the start of Vatican II, which was intended to open the church to the modern world and respond to the “signs of the times,” the church is gravely polarized between a progressive wing still eager for change and reform and a traditionalist flank focused on returning to what it sees as doctrinal fundamentals.

The sisters have been caught in the riptide. Most of them have spent their lives serving the sick, the poor, children and immigrants — and not engaged in battles over theology.

But when some sisters after Vatican II began to question church prohibitions on women serving as priests, artificial birth control or the acceptance of same-sex relationships, their religious orders did not shut down such discussion or treat it as apostasy. In fact, they have continued to insist on their right to debate and challenge church teaching, which has resulted in the Vatican’s reproof.

The former head of the church’s doctrinal office, Cardinal William J. Levada, said after his last meeting with the nuns’ leaders in June, just before he retired, that they should regard his office’s harsh assessment as “an invitation to obedience.”

“I admire religious men and women,” Levada said in an interview with The National Catholic Reporter. “But if they aren’t people who believe and express the faith of the church, the doctrines of the church, then I think they’re misrepresenting who they are and who they ought to be.”

The sisters say they see no contradiction in embracing the Catholic faith while also being open to questioning certain church teachings based on new information or new experiences.

The Leadership Conference has not taken a stand in favor of the ordination of women or the acceptance of gay relationships, but it has discussed such topics at its meetings. Members insist that open discussion of church doctrine is not only their right but is also healthy for the church.

They say their approach is no different from that of many Catholic priests and laypeople, not just those in the U.S. As evidence, they cite messages of support they have received from Catholic religious orders of men and women all over Europe, Asia and Latin America — as well as in the U.S.

“We make our vows, but our obedience isn’t blind,” said one mother superior, who, like others, did not want to be identified while the future of the Leadership Conference is in limbo. “Obedience comes from listening.”

Vatican II led to dramatic changes now taken for granted by many Catholics: allowing worship in local languages instead of only Latin, encouraging the participation of laypeople, and cooperating with other churches and faiths.

The council also approved a document, “Perfectae Caritatis” (“Perfect Love”), that instructed men and women in religious orders to study their orders’ founders and original sources, and use that inspiration to re-evaluate and renew their mission. The sisters say they took the instruction to heart.

“We were the ones who probably took Vatican II and ran the fastest and the farthest with it,” said Sister Janice Farnham, a retired professor of church history at the Boston College School of Theology and Ministry. “Sometimes our church leaders forget, we were tasked to do these things by the church. The church said jump, and we said, how high?

“The church said update, renew, go back to your sources, and we did it as best we could. We did it with a passion, and we paid dearly.”

The sisters after Vatican II had access as never before to higher education, and they went on to become scholars and theologians, chief executives of hospitals, legal aid lawyers, social workers and martyrs in countries like El Salvador. They took on issues including economic injustice, racism, women’s rights, immigration, interfaith relations and environmentalism — which for many years put them in collegial working relationships with bishops who were also engaged in those causes.

But the two popes who reigned for the last 34 years — first John Paul II and now Benedict XVI — appointed bishops who are far more theologically and politically conservative than their predecessors. Drawing on these popes’ teachings, this new generation of U.S. bishops has steered the church’s social priorities toward opposition to abortion, gay marriage and secularism.

The Leadership Conference was a thorn in the Vatican’s side even before 1979, the year its president at the time, Sister Theresa Kane, welcomed John Paul to Washington with a public plea to ordain women in the priesthood. The group has remained unified despite pressure from the Vatican by making decisions only after consulting its membership. It is hardly the small splinter group that some conservative critics have recently tried to portray.

The disciplinary action against the nuns comes just as U.S. bishops are struggling to reassert their authority with a wayward flock. The bishops are in the midst of a campaign to defend against what they see as serious threats to religious liberty — especially a government mandate to provide employees of Catholic institutions with health insurance that covers contraception.

But the prelates are well aware of polls showing that about 95 percent of Catholic women have used birth control at some point in their lives, and 52 percent support same-sex marriage — little different from the public at large.

The dissonance is of great concern to U.S. bishops and the Vatican.

“The church must speak with one voice,” Archbishop Carlo Maria Vigano, the papal nuncio to the United States, said in an address in June to U.S. bishops at their meeting in Atlanta. “We all know that the fundamental tactic of the enemy is to show a church divided.”

He added pointedly that at this “difficult time,” there is a special need for women and men in religious orders, and for Catholic universities, to “take on an attitude of deep communion” with the bishops.

© 2012 The New York Times Company