In a town where college alumni organizations are as plentiful as as people who won't admit they supported Richard Nixon, the Yale Russian Chorus alumni is a rare assemblage of dedicated friends.

One might understandably ask: when did an entire Cossack chorus defect to New Haven? Don't worry, you haven't missed a major international incident that might come up in conversation. It didn't happen that way.

The Yale Russian Chorus is an all-American group born, like so many inspired ideas, on impulse one day back in 1954. Denis Mickiewicz, the founder, was a quiet, unassuming Yale freshmen enjoying his first year in the United States after living in Austria, where he had immigrated in 1939 from Latvia, his cherished homeland.

"A professor from Latvia asked me to give a lecture on Russian music to the Russian Club, and I thought it would appeal to the boys if they sang the music themselves," Mickiewicz, today a professor of Slavic languages and literature at Emory University in Atlanta, remembers.

Now, 27 years and hundreds of alumni richer, the spirit of the chorus has spread worldwide, sparked by local alumni organizations that periodically get together to sing the unchanging lyrics (in Russian) and to join the current Russian Chorus whenever it comes to town.

Of all the alumni (scattered throughout six continents -- the chorus member who was stationed in Antarctica left two years ago) who receive sporatic newsletters from kindred souls at Yale, the Washington area group is the only one that actually performs as an alumni organization.

Its membership of about 20 have chosen careers as diverse as the repertoire they enthusiastically chant. Yet all share a love for the rich folk and liturgical music, a respect for the culture of Russia and an understanding of its people, and -- most of all -- unyielding allegiance to the group's sense of camaraderie, which lies deep in the hearts of those who have sung with it.

"The chorus has definitely influenced my life, probably more than any other single factor," declares Nick Danforth, a designer of education projects for Westinghouse Health Systems who, incidentally, travels frequently to Africa and Asia but not to Russia.

Danforth recalls the thrust of that influence developing when he toured the Soviet Union with the chorus in 1962.

"When you're told all your life that Russia is the enemy and then suddenly find out it's interesting and as beautiful as the Russian culture is -- well, it changes your whole life. I've never been the same since," he said.

Others chorus members speak as fervently of the group's influence on their lives.

The Rev. John Boles, now 41, a Presbyterian minister and former pastor of the Capitol Hill Presbyterian Church, explains:

"Anyone who's an alumnus sort of stays with the group because they're always allowed to sing with the us wherever it performs. It's not like you're in or out.Once you're a member, you're always a member," he said.

Since the centuries-old songs never change, the concerts don't vary much. That changeless quality of both words and emotions reached a triumphant peak in 1978 when the chorus convened for its 25th anniversary concert at New York's Carnegie Hall.

Of the 125 who came to the long-awaited reunion, 30 were members of the current chorus. Nearly all the Washington alumni attended; four flew in from London; at least four came from California and others came from Alaska, Sweden and Africa -- not to mention many other states of the union.

To see that the chorus attracts a wide range of people, one need only look at the alumni who now live in all corners of the Washington metropolitan area.

John Shattuck, 37, heads the Washington office of the American Civil Liberties Union. John Agosta, 26, is an enviornmental scientist with the EPA. Stephen Greene, 28, is a freelance writer. John Zucker, 25, and Mike Mobbs, 32, are both lawyers with local firms.

The list goes on. Gunnar Knapp is an economist for Resources for the Future; Bill Cline is an economist with Brookings Institute; Mark Brown works at a Russian bookstore in Rockville and sings with the Paul Hill Chorale. Bill Watson is an executive secretary with Approprite Technology International.

The alumni performers have sung at parties in the area, at the opening of an exhibition of Impressionist paintings from the Soviet Union shown at the National Gallery of Art in 1973, at Boyles' son's christening last May and at the Capitol Presbyterian Church earlier this month.

Politics struck a heavy blow to the group last spring when their scheduled appearance at the opening of the Hermitage Collection from Leningrad was canceled after the Soviet invasion of Afghanistan.

However, the rhythmic, melodic shoutsof their performances, which enhance feelings of brotherhood, and the delicate harmonies of their liturgical pieces will be heard once again when the alumni chorus performs at 8 p.m. Saturday for Anesty International's program dedicated to human rights in the Soviet Union, at the Jack Rasmussen Gallery, 313 G St. NW.

Robert Drinan, former congressman from Massachusetts, and dissenters from the Soviet Union will be among the guests of the guests of the program.

Saturday's concert promises to be the beginning of more to come. "We're talking about performing more as a professional group in the future," Agosta said this week. If they do, Washington is in for some spirited times.