They caught sight of the swelling crowds that morning as they left the Capitol after meeting with congressional leaders, and they knew that the day--and the movement--would make history.

"We could see hundreds and hundreds of people, a sea of humanity, going to the Lincoln Memorial," recalls John Lewis, then the 23-year-old chairman of the Student Non-Violent Coordinating Committee. "It was a great feeling--they were all there."

Lewis was the youngest of the 10 civil rights, religious and labor leaders who convened the 1963 March on Washington. The patriarch of the group and the major organizer of the gathering on the Mall was A. Philip Randolph, president of the Brotherhood of Sleeping Car Porters and a veteran of decades-long antidiscrimination struggles.

With only eight weeks to organize the march, and seeking as broad a constituency as possible, Randolph and his hand-picked coordinator, Bayard Rustin, enlisted: Roy Wilkins, executive director of the NAACP; Martin Luther King Jr., head of the Southern Christian Leadership Conference; James Farmer, director of the Congress of Racial Equality; Whitney Young, executive director of the National Urban League; Walter Reuther, president of the United Auto Workers; Dr. Eugene Carson Blake, director of the National Council of Churches; Rabbi Joachim Prinz, president of the American Jewish Congress, and Mathew Ahmann, executive director of the National Catholic Conference for Interracial Justice.

Twenty years later, the March on Washington still stands as their shining achievement. But the issues that brought them all together that day are more complex now, and the changes of the last two decades have been profound, both for the civil rights movement and for the surviving organizers of the march, only two of whom--Lewis and Farmer--definitely plan to attend today's anniversary gathering.

"Twenty years ago the segregation in places of public accommodations, housing and jobs was very open, and we had just been through a series of nonviolent demonstrations that had attracted worldwide attention," Lewis, now an Atlanta councilman, said recently. "We came to Washington looking upon government as a sympathetic leader."

There is "less drama" surrounding today's anniversary march, said Lewis, who will participate in it, and the government, under Ronald Reagan, "is not as sympathetic" to minority concerns. "And, of course, we don't have the moral leader of the movement, Doctor King."

King, whose "I Have a Dream" speech electrified the crowd and became the rallying cry for racial equality, was assassinated in Memphis on April 4, 1968. He was 39. The leader of the SCLC won the Nobel Peace Prize a year after the march and continued his work on behalf of civil rights, working for passage of antidiscrimination legislation. At the time of his death, he had become a critic of the Vietnam War and had begun advocating increased economic opportunities for minorities.

Gone, too, are other civil rights giants of the era--Randolph, Wilkins and Young.

Randolph, who organized the first major black labor union in the nation, died in 1979 at the age of 90. Wilkins, a Mississippi slave's grandson and another civil rights veteran, died in 1981 at the age of 80. Young, who pursued jobs for blacks among the nation's top corporations and drew criticism when his conciliatory nature extended to the Nixon White House, died in a drowning accident in 1971. He was 49.

Reuther, who was in the small group of labor leaders who helped sponsor the march, used the event to deliver a stinging attack on the AFL-CIO for its refusal to join. He died in a plane crash in 1970 at the age of 62.

For the surviving march organizers, memories of the March on Washington and of the era itself are hauntingly vivid. And most of them share a sense of sadness that the goals articulated that day have not been realized.

"The status of the black community is not substantially better off economically," argues Ahmann, a 51-year-old layman who is now an official with the Washington-based National Conference of Catholic Charities. Because of a recent operation, he said he will be unable to attend this march.

Rabbi Prinz, 81 now and living in Orange, N.J., said the 1963 march "was a very great event because so many people came and because it was completely peaceful. But I don't think we've made much headway in the past 20 years."

Blake, however, said, "1963 was a great year for civil rights, and we've been better ever since."

Now 76, the Presbyterian minister, who later headed the World Council of Churches from 1966 until his retirement in 1972, lives in Stamford, Conn. He plans to watch the anniversary march on television.

That's what CORE leader Farmer did 20 years ago when he and other demonstrators were jailed in Plaquemine, La., five days before the march. There wasn't enough money to bail everyone out, and Farmer refused to leave the others, despite pleas from march coleaders that he should come to Washington to speak.

"It was disappointing, but I was doing what I had to do--the work of the movement," said Farmer, now 63, who asked Floyd McKissick, then CORE's national board chairman, to substitute for him. This time around, even though he has been fighting blindness in recent years, "I intend to be there."

After resigning from CORE leadership in 1966, Farmer headed a national literacy drive, taught at universities in Pennsylvania and New York and, until he resigned in frustration, was an assistant secretary at the old Department of Health, Education and Welfare during the Nixon administration. Between 1977 and 1982, he was executive director of the Coalition of American Public Employees.

Today, Farmer lives in Fredericksburg, Va., is writing his autobiography and gives the bleakest assessment of how the civil rights movement has changed in the intervening two decades.

"In the early '60s we were very popular people--no one would think of having a cocktail party without one of us there," said Farmer. "But the image of blacks now is less positive and more negative. Most people feel there is no longer any discrimination, or if there is, it's in the reverse."

Farmer's march substitute and CORE successor, McKissick, now 62, started developing Soul City, N.C., a "new town" intended to showcase the possibilities of black capitalism, in 1969. The project lost federal funding in 1980, after a government investment of $31 million, but he is still a resident and one of three developers there and remains hopeful about the town's growth.

Lewis said the Vietnam war, horrifying assassinations here and violence abroad "tended to sap the energy and hope of a lot of people. Dreams were diluted, but not destroyed."

In 1966, the SNCC leader was ousted from that post--and replaced by Black Power advocate Stokely Carmichael--because members of the group considered Lewis too close to Dr. King. Yet only three years earlier, Lewis noted wryly, he was pressured to tone down certain passages in his speech for the march because Archbishop Patrick O'Boyle of Washington thought some of his remarks too inflamatory.

A veteran of sit-ins and Freedom Rides in the South, Lewis, 43, later directed the Voter Education Project, which was responsible for registering 4 million black voters between 1970 and 1977. He spent three years during the Carter administration as an official at ACTION and is now serving his second term on the Atlanta City Council.

Lewis lists the crowd size and Dr. King's speech as among the highlights of the march, but he has equally fond memories of the group's White House visit later that day. Though he had endorsed the march, President Kennedy had had initial reservations about the event, fearing its impact on pending civil rights legislation and the 1964 presidential contest.

"But when we got to the White House, he was just beaming," said Lewis, "and we all had a glass of orange juice."