The landmark Supreme Court decision to desegregate the nation's schools came 50 years ago tomorrow, but Jesse L. Jackson can remember the day vividly.

The civil rights activist was 11 years old, sitting on a porch in Greenville, S.C., when word came on the radio. Another youngster asked what it meant to integrate, and some older folks explained that it was like taking salt and pepper and shaking them together.

"When will that happen?" the first person asked.

"No time soon," came the response.

Jackson's anecdote drew laughs yesterday during a day-long seminar at the National Theatre to commemorate the ruling in Brown v. Board of Education, a decision that gave hope to millions of black Americans that they would gain access to an education equal to that provided to whites. But a half-century later, Jackson and other leaders in politics, education, law and civil rights said, the legacy of the high court's historic decision is being threatened by deep-rooted social, economic and educational inequalities.

"I have a proposal: Let's start a third revolution here," Constance L. Rice, co-founder of the Advancement Project, a racial justice organization, told the crowd of a few hundred people and a television audience on C-SPAN. "We need to celebrate the achievement of Brown, but we have an obligation to change conditions we face today. It's a question of political will."

The event, sponsored by the NAACP Legal Defense and Educational Fund and broadcast personality Tavis Smiley, was called "Unfinished Agenda" and was ostensibly to look back at the Brown case. But much attention was spent encouraging people to make a difference at the voting booth in November of this presidential election year. President Bush and his top aides took a pounding from the panelists who questioned Bush's commitment to affirmative action and other educational initiatives.

At a midday news conference, the panelists were asked another politically loaded question: What did they think of the District's plan, backed by Mayor Anthony A. Williams (D), to allow some students to use vouchers to attend private school in the nation's first federally funded vouchers program?

"Whatever Brown was about, it was not about vouchers or high-stakes tests," said Theodore M. Shaw, who heads the NAACP Legal Defense and Educational Fund. "It's about desegregation. . . . We understand why parents in a failing system would find vouchers attractive. You have only one chance to educate your child. But systematically, vouchers are bad. We should not take one dime from public education and divert it elsewhere."

The 10 panelists in the morning session agreed that the country's schools are still largely failing black and Latino students, as well as poor whites. They complained about the ongoing achievement gap that has shown that black and Latino students generally score more poorly on standardized testing than their white and Asian peers. However, the speakers engaged in spirited debate over some issues.

For example, some panelists bemoaned the fact that some black students belittle peers who excel in school by charging that they are "acting white." James M. Jones, a professor at the University of Delaware, recalled that some students once told him that "excellence is a counterrevolutionary concept. . . . That created the erroneous idea that failing at school is a validation of your black heritage."

Lani Guinier, a Harvard University professor, challenged the notion that members of the black community had low expectations for one another. She said that many white-dominated schools routinely fail to push black students to take Advanced Placement courses. Conversely, at predominantly black schools, where blacks are in high-level courses, Guinier said, "they're not accused of acting white; they are saluted."

The panelists kept the crowd engaged with thoughtful analysis, impassioned speech and even light humor. Noting that too many youngsters want to become basketball players, Jackson quipped: "I see guys in wheelchairs who are trying to figure out how to dunk."

Ultimately, despite the star power on stage, the panelists emphasized that it is up to ordinary citizens to push for greater equity in schools through political action.

"What made Thurgood Marshall more revolutionary than most of the megachurch organizations today is that we live in our faith but we live under the law," Jackson said of the man who won the Brown case and later became a Supreme Court justice. "Those who change the law are more revolutionary."

Jesse L. Jackson, center, laughs with Karen Narasaki, to his right, as panelists discussing Brown v. Board of Education prepare for a photo. Wade Henderson, center, executive director of the Leadership Conference on Civil Rights, talks with Marisa J. Demeo, left, and Professor Lani Guinier.Cecilia Marshall, widow of Thurgood Marshall, who argued Brown v. Board of Education and became a Supreme Court justice, attends the seminar.