It accused Roman Catholic cardinals in this country who took part in a 1958 papal conclave of "voting in a political election in a foreign state" and asked that their citizenship be revoked; in 1967, it sought an injunction against the sale of a Christmas postage stamp with a madonna and child motif, because, it said, the stamp promoted the Roman Catholic religion.

In 1949, it said the Roman Catholic hierarchy was "more dangerous and clever than communism;" it asked the Federal Communications Commission to deny television licenses to Jesuit universities in New Orleans and St. Louis on the grounds that the Jesuit order was "an alien organization."

Over the years, Protestants and Other Americans United for Separation of Church and State, as it was called in those days, has shed its anti-Catholic mien. But it remains extremely active in monitoring the First Amendment separation of church and state.

This week the organization, which has changed its name to Americans United for Separation of Church and State, was in the limelight because of a Supreme Court decision. The court ruled 5-to-4 that Americans United had no standing to sue to block the transfer of government property to an evangelical Christian college because the transaction did not hurt the group's members directly.

The decision is expected to provide new obstacles to public interest law suits in general and church-state issues in particular. An abiding concern for the separation of church and state is Americans United's sole reason for existence.

"We like to say we are the only organization in America devoted exclusively to the separation of church and state," explained the Rev. Gene Puckett, executive director of the organization, which uses the dual approaches of education and litigation. Puckett said that Americans United, with headquarters in Silver Spring, is involved in "20 or 25 cases over the country," but has no others currently before the Supreme Court.

Lee Boothby, the organization's legal counsel, said this week's Supreme Court decision was indeed "a blow" and would raise problems for any actions dealing with the "establishment clause" of the First Amendment--the stipulation that Congress shall make no laws to establish a religion.

But not all Americans United's cases hinge on that part of the Bill of Rights, he said.

Americans United is sometimes viewed as a religious version of the American Civil Liberties Union, although Puckett is not fond of that analogy. "Chances are that our position on an issue would be the same as the ACLU's," he said. But then he added, "The ACLU is generally perceived as anti-church and anti-religion, while we are perceived as definitely for the church."

Americans United's 15 trustees are all church leaders, Puckett said, and much of the organization's annual $1 million budget comes from church-related sources. He and his professional staff of 11 spend a fair amount of time attending denominational meetings, interpreting the group's work and church-state concerns

Many church bodies write allocations to Americans United into their own regional or national budgets. They have also been known to eliminate them from church budgets when the organization's passion for church-state separation strikes too close to home.

From the beginning, Methodists were among the strongest supporters of the organization, but in 1966, the Baltimore Conference of the Methodist Church voted to drop its annual $500 allocation, complaining that the organization was "anti-Catholic." Glenn L. Archer, then the director, retorted that a more important reason for cutting off the funding was the organization's court challenge of a $500,000 state grant to the Methodists' Western Maryland College. The organization won the suit, and Methodists eventually returned to the fold.

That the organization was anti-Catholic in its beginnings would be hard to dispute. The late Cardinal Richard Cushing once called the group "a refined form of the Ku Klux Klan." Protestants and Other Americans United for Separation of Church and State, was in fact founded in 1948 to oppose President Truman's appointment of Gen. Mark Clark as his personal envoy to the Vatican. POAU contended that such a move indicated "religious freedom is in peril."

In the light of the last 20 years of ecumenical understanding, the depth of the anti-Catholicism of those days is jarring.

But it was a time of few contacts, and therefore little understanding, between religious communities.

It was an era when anti-Catholicism was part of the dominant culture.

In its early years, POAU:

Called on the House Un-American Activities Committee to investigate "the intentions, scope and achievements of Vatican espionage here," charging that Catholic clergy had learned "American secrets hardly anyone except the president knows"--this was at a time when some of POAU's staunchest clergy supporters, themselves under fire by the committee, were assailing the panel's methods.

Offered to fund "any bona fide Catholic or ex-Catholic" who was married in a civil ceremony and wished to sue his bishop for slander because of a Catholic statement at the time that civil marriage for Catholics results in "low and abominable concubinage."

Flooded Congress with letters in 1962, protesting the waiver of portions of Washington's building code to accommodate plans for the Watergate complex. Citing the substantial investment of Vatican funds in the Watergate venture, POAU claimed that "a Vatican-created corporation mounted such pressures for code changes that the government yielded."

But its main struggle, and one that it continues today, raged around the issue of state aid to private schools. Throughout its history, it has remained adamantly opposed to any such aid whether in the form of textbooks, services to the handicapped, transportation, tuition tax credits or direct cash grants. But its opposition today is not limited to Catholic schools.

POAU's anti-Catholicism began to diminish in the '60s with the growth of the ecumenical movement, and the growing condemnation of bigotry by society at large.

Puckett, a Southern Baptist clergyman who has headed the organization for three years, is emphatic about the group's move away from its earlier anti-Catholicism. "We have very definitely, both by philosophy and by conviction, gotten away from that," he said, adding that Americans United today has Catholics on its staff and on its advisory board.

At its inception, POAU included some of the leading Protestant churchmen of the era--men such as Methodist Bishop G. Bromley Oxnam, Christian Century editors Charles Clayton Morrison and Harold E. Fey and Princeton Theological Seminary President John A. Mackay. This city's largest churches, and even Constitution Hall, were required for its annual meetings and rallies.

In contrast, last year's annual meeting of Americans United fit nicely into the 4-H Center in Chevy Chase, with space left over for several other gatherings. Puckett attributes the shrinkage to the changing times.

Puckett says the organization today has 46,000 dues-paying members and about 120 chapters nationwide, ranging in size from the more than 100 people in St. Louis to a mere handful.

According to Puckett, "the greatest number" of financial contributions come from Baptists, both because there are so many of them and because Baptists have long been sensitive to issues of religious liberty. But "the largest per capita contributions," Puckett said, "come from Christian Scientists, Seventh-day Adventists and Jews."

As evidence that Americans United is not influenced by sectarian bias in its drive for church-state separation, Puckett says: "During the visit of the pope, we were involved in Philadelphia, against the Catholic church" in a suit to bar the then mayor of Philadelphia from using public funds for construction of a platform for the pope's appearance, "and we won."

"But in Washington," he continued, Americans United opposed the effort of atheist Madalyn Murray O'Hair to keep the pope from celebrating mass on the Mall, "and we won that, too."

He added, with unmistakable satisfaction, "We got criticism from both sides, on both actions."