Before he retired to tend to his forest, write books and go to bed every night by 10 p.m., the Rev. Duncan Howlett put in a decade at his pulpit in Washington pricking the consciences of his fellow white liberals.

He was a high-profile preacher whose sermons at All Souls' Church on 16th Street NW made the newspapers week after week. He preached about "the white man's burden" and was recognized as one of five whites in Washington most trusted by blacks. When his associate pastor, the Rev. James J. Reeb, was clubbed to death by segregationists in Selma, Ala., in 1965, Howlett wrote a book entitled "No Greater Love." He gave up his pulpit in 1968 to make it available to a black man. And he marched in Alabama and Mississippi and in what he calls "the Great March on Washington" 20 years ago.

"In the decade of the '60s, civil rights was my issue. I made the most of it," says Howlett, now 77 years old.

A gaunt New Englander with sinewy arms, flat stomach and fluffly white eyebrows, Howlett lives with his wife (their four children are grown up) in a restored hilltop farmhouse that looks west to the White Mountains. He keeps in shape chopping wood on his 1,000 acres of forest land.

The son of a well-to-do Boston painting contractor (it was family money that helped buy the forest), Howlett attended Harvard, Harvard Law and Harvard Divinity School. A self-proclaimed "idealist," Howlett saw the civil rights movement as more than just guaranteeing "technical rights for the black man." The movement, he told his congregation in the 1960s, was the sine qua non for the future of the United States as a unified nation.

The march in Washington, with its mix of blacks and whites, its high-minded speeches and its nonviolence, was for Howlett "one of my most joyous days."

"You don't understand the euphoria until you first grasp the anxiety that existed throughout American society and in Washington over the gathering of a quarter of a million people on this explosive issue," Howlett says.

After conducting a special service at All Souls' Church on the morning of the march, the minister led 1,500 Unitarians carrying placards and banners down 16th Street to the Mall.

"Only eight years before that march, the break in the iron hand of segregation on the South occurred when Rosa Parks sat down on the bus" in Montgomery, Ala., says Howlett, warming to his memories. "And then began the slow, anguished process of sit-ins at lunch counters. From Rosa Parks sitting down on that bus to a quarter of a million people gathering in Washington--that is an achievement. It was a high point in a society struggling to achieve an ideal that it had only recently formulated."

The rise of black power and the urban riots and deaths that marked the late '60s do not, in Howlett's mind, sully that day's dream of an integrated America.

"I don't think anybody was under an illusion that this march represented a permanent state of affairs," says Howlett. "This was simply an incredible demonstration of what might be. If you had asked me that day if this were where we were, I would have said, 'No. Tomorrow we go back to work.' "

Howlett continued to work in the civil rights movement beyond the point where many white liberals had moved on to other causes. In 1966, marching with about 10,000 people between Memphis and Jackson, Miss., Howlett recalls seeing very few whites. He noticed, too, for the first time that a few black marchers seemed to hate the sight of his white skin.

"In that march I noticed the tone of militancy was rising. The blacks who were getting attention, getting press, were those who were not content just to march. It became clear that the militants were taking over and the civil rights movement as we knew it was at an end."

Howlett told his congregation that even though he condemned the riots in Watts, Newark and Detroit, he saw black anger in a white-controlled society as inevitable. "We have got to allow it, expect it, forgive it," he says now.

Howlett left the pulpit in 1968 to go to work in the presidential campaign of Hubert H. Humphrey, for whom he says he "fought, bled and died."

After Humphrey's defeat, for which he blames "the so-called kids at the Democratic National Convention in Chicago who were for ending the Vietnam war--never mind anything else," Howlett came up to Maine to retire, write his fifth book and study forestry.

Twenty years after the March on Washington, he says blacks have accomplished more than he ever expected, but the distance left to go "is almost immeasurable." For himself, however, Howlett says he worked for an integrated society as hard as he knew how.

"I gave it everything I had," he says.