There was a time when the bishops of the Roman Catholic Church in this country were viewed, correctly, as one of the bulwarks of conservatism.

At their 1980 annual meeting here last week, it became unmistakably clear that this no longer is the case. In the choice of their leaders, in their resolutions and actions on social justice issues, in their developing sensitivity to feminist concerns, in the spontaneous applause -- and groans -- with which they received comments and speeches by their number, the more than 250 bishops, established that the American hierarchy is a progressive force in American life.

Consider their response to the feminist issues. Only two years ago, feminists seeking to engage individual bishops in conversation on a feminist issue, such as ordaining women as priests, waited in hotel corridors outside the bishops' meeting area. With only a few exceptions, the prelates strode past them, eyes straight ahead, giving no sign that the women were even there.

This year, by a massive majority, the bishops voted to petition the Vatican to purge the church's liturgy of sexist phrases that "cause great pain" to women, as Milwaukee's Archbishop Rembert Weakland put it. And they pledged to apply the same standards of nonsexist language to the final editing of resolutions and other documents adopted during the meeting.

At one point in last week's meeting, Detroit Auxiliary Bishop Thomas Gumbleton made an impassioned plea for the church to take a forceful stand against nuclear warfare. "The political situation today means that the time is very short before a [nuclear] holocaust could happen," he said. He traced national policy from one of revulsion against nuclear warfare a decade ago to today, when a president-elect "says we should have nuclear superiority" and a vice president-elect speculates that the United States can win a nuclear war, Gumbleton said.

"With that kind of thinking going on, we are even closer to nuclear holocaust," he said. Gumbleton is one of a handful of outspoken peacenik bishops who are active in antiwar, antinuclear movements. No one was surprised at what he had to say. But when he made similar appeals a few years ago to his brother bishops to speak out against the Vietnam war, they suffered him in embarrassed silence, then went on with their business.

This time they greeted his intervention with sustained applause. "This is a very serious issue in which we are intensely interested and about which we are all concerned," said one retiring president, Archbishop John Quinn. He suggested that the bishops should begin work on a policy statement on the question.

This is a far cry from the way the late Cardinal Francis Spellman, little more than a dozen years ago, dismissed the ambiguities of U.S. involvement in Southeast Asia: "My country, right or wrong, my country."

In their choice of Archbishop John R. Roach of Minneapolis as president and Bishop James Malone of Youngstown as vice president, the bishops chose leaders for the next three years who can be expected to move the American church further along the reforms in both church and society that were envisioned by the Second Vatican Council.

Roach, 59, is a warm, open man with a track record of running his archdiocese with an easy hand on the reins. Archbishop of St. Paul-Minneapolis for five years and an auxiliary four years before that, he initiated and supported local church-sponsored efforts for divorced Catholics, for Indian-Americans and Hispanics and established a vigorous commission to work for a larger role for women in both church and society. He has leaned on his people to support efforts to reduce racial tension and has required all religious education programs to include lessons on the church's denunciation of racism.

Last year during the American tour of Pope John Paul II, Roach traveled on one of the press planes instead of with the papal party, chatting affably with reporters at long airport waits. In a part of the country where Lutherans are in the majority, Roach has been honored for his efforts for interfaith cooperation.

Malone, 60, is also widely known for his ecumenical leadership. Three years ago the religious leaders of the Youngstown area -- Protestant, Catholic and Jewish -- joined in an unprecedented effort to mobilize the community to take over and operate the closed steel plants. The hoped-for government aid that the venture required did not materialize and the plan died, but the ecumenical network of the churches has survived.

A telling factor in the bishops' elections last week is the fact that in the field of 10 candidates for the two top offices, the three who could be characterized as reasonably conservative garnered a cumulative total of only about 15 percent of the votes.

The new liberal cast of the American hierarchy is due in large part to the kind of men selected as bishops the past six or eight years. They are as likely to have been plucked from embattled inner-city parishes or a stretch of mission service in underdeveloped nations as, a generation ago, they were likely to have come from prosperous suburban parishes or chancery offices.

What is significant is that even after their elevation to the episcopacy, many of these new bishops have spurned the traditional episcopal palaces and are continuing to live in the inner city, in close contact with their people.

In addition, they are younger men, men who have been excited -- rather than threatened -- by the revolution in the church that was wrought a dozen years ago by the Second Vatican Council. The crop of 174 bishops -- about 60 percent of the American hierarchy -- set into place over the last seven years by Archbishop Jean Jadot, who until last September was the Vatican's man in this country, is now producing a significant harvest. That is one of the reasons observers are watching anxiously to see who the Vatican names as Jadot's successor.

There are some signs the American church may be pushed in ever-more progressive paths in the years ahead. As the younger, more liberal bishops gain experience, confidence and seniority, their voice will grow louder and their influence increase. Conservative Catholics have real cause for concern.

The signs were already there at the 1980 meeting. Retired Cardinal John Carbury of St. Louis is probably the most outspoken conservative member of the hierarchy. On the frequent occasions he takes to the microphone, the tenor of his interventions are predictable. This year, for the first time, clearly audible groan swept over the house every time Carbury was recognized to speak. In a body ruled so long by civility and deference to senior members, it was a telling phenomenon.

Nor are some of the younger bishops inhibited by their relative inexperience. In the final minutes of this year's meeting, Auxiliary Bishop James P. Lyke of Cleveland, a member of the club for less than a year, all but demanded a promise that the body would act at its next meeting on a comprehensive statement on health care. The statement, three years in the works, was tabled earlier, some charged, because a section asserting the right of collective bargaining for workers in Catholic hospitals rankled the Catholic Hospital Association.

Lyke was outraged, and he had let it be known in the earlier discussion. As one of the church's five black bishops, he was annoyed at what he viewed as dilly-dallying on an issue of vital concern to blacks; both on the question of the right of everyone to health care and the collective bargaining question, a vital concern to the large numbers of blacks who work at low-level, low-pay positions in Catholic hospitals.

"In future meetings, I would plead for a hierarchy of truth and values in the discussion of certain items," he said, clothing his cheek at criticizing his elders in theologically acceptable terms. c

Then he went on to blast his brothers for spending close to an hour tinkering with the wording of a new prayer for the new American Indian saint, Kateri Tekakwitha, while bouncing the health care statement back to committee without discussion.

The Roman Catholic bishops in this country are clearly moving in a liberal direction. If, as is generally conceded, the Vatican is tending in a more conservative direction, there could be some interesting times ahead.