Now that the placards have been laid aside and the Mall swept free of the debris of last Saturday's March on Washington II, what do we see as a lasting result or fleeting consequence? The coming together of 300,000 people was an important, moving statement, as was Muslim leader Louis Farrakhan's message of reconciliation.

But the march was also a stage on which various scenarios were being played out, and the one that could have the most significance for the future starred Jesse Jackson and featured as the supporting cast what march organizers called the New Coalition of Conscience.

Last Saturday's march made visible the elements everybody agrees are necessary for a serious black candidacy, and it showed that the potential for a coalition exists. At the same time, it showed a disappointing failure by Jackson to seize the opportunity.

Jackson has always envisioned a black candidate needing a "rainbow coalition of the rejected," with, according to Jackson, 18 million black voters as the cornerstone, that would draw on 6 million Hispanics and 6 million young people graduating from high school, as well as women, Native Americans, poor whites, and some white liberals and moderates. Most of these elements were present at the march. Their support and the size of the turnout indicated they recognized there are issues around which they could rally, and it was clear that the focus for many of them was Jackson.

I stood beneath that sweltering sun feeling the potential for a "new populism," that movement long latent in the American system, with Jackson as the "new populist" and the Coalition of Conscience as a natural constituency.

Jackson's bid for coalition politics has been successful this spring and summer, and his speeches have repeatedly embodied populist ideals. In May, when he became the first black man since Reconstruction to address a joint session of the Alabama legislature, white lawmakers quickly warmed to his attacks on foreign nations for unfair trade practices that have cost Alabama steel mills and rubber plants thousands of jobs.

His railing against Honda and Toyota replacing Buick and Chrysler in the American market is one of the little-noticed economic recovery issues on which he has chosen to focus his new populism, along with the broader issues of racism, sexism, poverty, the environment and a newly militaristic foreign policy.

Populism is a popular title this year, with politicians from across the political spectrum battling to lay claim to the designation and to the heritage of the massive rural movement that played a powerful role in American politics from the l890s to the l930s. That label became increasingly associated with social conservatism and at times racism. Many among the younger generation of politicians say the historical populist movement became perverted, and argue that the founders wanted to build a coalition of the dispossessed of all races.

That, of course, is Jackson's battle cry, and it is the foundation of the true "New Populism."

Saturday's march helped to prove that such a coalition of the dispossessed can in fact be brought together, but as the crowd waited for Jackson to speak, the question that remained was whether he could rally and lead such a group.

He missed an opportunity. He rehashed old ideas such as the benefits of voter registration and enforcement and spent precious moments on his chant, "I Am Somebody." That was preaching to the converted. He could have better used the brief time allotted him to analyze the accomplishments of the past few months and articulate some kind of agenda for the future.

In all fairness, he was under pressure from other black leaders not to turn the event into a Jackson rally, and maybe he was being a team player by playing down his personal agenda. So his failure Saturday may not mean that he will ultimately fail to mobilize the coalition in the future.

And even though at times last weekend the coalition seemed held together with Scotch tape and glue, we know that if it could rally for the march, it potentially could rally around a black candidacy. If Jackson, the New Populist, can find a new opportunity to inspire it, the results could be dramatic, indeed.