David R. Jones, now president of the Community Service Society in New York, recalled milling about in Washington in 1963, a 15-year-old there with classmates from a lefty school in Manhattan. Then Dr. King began to speak, and they fell quiet. “I never saw that kind of a speech,” Mr. Jones said.  He was transported. But the years ahead often cast a deep shadow. Mr. Jones, who is black, was beaten by the side of the road in Maine. He fought for decades to integrate middle-class housing developments and saw young whites wave watermelons at black marchers in Brooklyn. There were great victories, too, not least the election of dozens and dozens of black members of Congress, a few senators, and in his own city, Mayor David N. Dinkins. But he is left with a chary view of history’s march.  “Obama doesn’t have all the burdens of my generation,” Mr. Jones said. “We have one foot in both eras. We’re still living out a lot of anger.”  The Rev. Walter E. Fauntroy can bubble with anger still; his 75 years have not dulled his outrage. He served as the District of Columbia’s delegate in the House in the 1970s and 1980s, and often raged at what he saw as the racism of denying Washington statehood and full voting rights.  Years earlier, as a 30-year-old, he was asked by Dr. King to coordinate the logistics for the March on Washington. Those were precarious days; just a week before, white segregationists had marched through Washington carrying signs reading “Martin Luther Coon go home.” When he traveled across the Potomac to Virginia, he rode in the back of the bus.  “People ask what has changed, and I say don’t trivialize the changes,” Mr. Fauntroy said. “I’m seeing the fruit of the changes that began in 1964. I was close to Bobby Kennedy. He said to me: ‘You know, America’s going to change. Forty years from now, a black man could achieve what my brother has achieved.’ ”  At least 20,000 whites were among the marchers who stood on the Washington Mall that hot and sticky day 45 years ago. Many had ventured south to work for civil rights in the hamlets of Georgia, Alabama, South Carolina and Mississippi.  Cappy Harmon, 59, remembered her father, an Episcopal minister who had been jailed in North Carolina, loading her two sisters and her mother into a Volkswagen bus and driving south from Roxbury, Mass.  “It was one of those times when it was very clear what was right and what was wrong,” Ms. Harmon said.  The years to come offered less clarity. The civil rights movement fractured, Dr. King was assassinated, and Ms. Harmon, who works at Atlanta Habitat for Humanity, spoke of exploring her views with a new clarity.  “I was learning about my own racism, which was ingrained in ways that you don’t always understand,” she said. “It really was a long journey for all of us. But, in a way, an exciting one, too.”  On Thursday night she plans to watch the candidate she has supported from the beginning accept the nomination, an experience she likens to that march 45 years ago. “It’s incredibly exciting,” she said.  And yet, even for these veterans, fear can temper their joy. They have seen too many defeats — many supported Jesse Jackson’s two losing runs at the nomination in the 1980s — to assume a near majority of white voters would elect a black man.  Ms. Woods-Jones, president of Black Women Organized for Political Action, nearly vibrates with the joy of living in this moment. She describes her 35-year-old son sitting on a couch with her grandson, crying as he watched Mr. Obama this week. This is a hopeful woman tempered by history.  “The concern for me, well, America has grown to a point,” she said. “Having said that, there will still be those who go into the booth, their closet, and can’t vote for him. I hope, I pray, most of us are past that.”  A little earlier, Archie Spigner, a retired New York city councilman from Queens, sat on a park bench in Denver in his pin-striped suit. Gray now, he was a Young Turk in 1963 when he and other activists forced their white-run union to send buses to Washington. He came back enraptured but noticed that the world had not changed.  Mr. Spigner recalls real estate agents who would not return calls, burger joints in Queens that would not hire his constituents. Months ago, he endorsed Hillary Rodham Clinton, because she is his state’s senator (he harbors a lifelong allegiance to the powerful Queens Democratic Party machine) and because she might have had an easier joust with history.  “Would it have been easier with Hillary? Maybe,” he said. “We’re rolling the dice. As a black man, I hope, I hope.”  Ralph Blumenthal contributed reporting from New York, Robbie Brown from Atlanta, and Rachel L. Swarns from Washington.  A version of this article appears in print on , on page A1 of the New York edition with the headline: 45 Years Later, Witnesses to Dr. King’s Dream See a New Hope. Order Reprints| Today's Paper|Subscribe
At least five people who saw Dr. Martin Luther King Jr. at the March on Washington in 1963 traveled to the convention.