"MAMA, WHERE are you?" the little girl squealed as she struggled to hold on to an oversized poster of Martin Luther King, Jr. and keep up with the crowd marching to the Lincoln Memorial in the 96 degree heat of the Capital Mall August 27.

"Here I am," came a reassuring voice behind her, along with a mother's squeeze. You won't get lost today. We're all walking the same way, and we'll all get there together."

Five thousand people from Eastern Massachusetts walked the same way as 250,000 Blacks and whites, dressed in Sunday suits and bathing suits, arrayed in families and interest groups, all marching on Washington to commemorate the 20th anniversary of King's "I Have a Dream" speech and rediscover the moral impulse of the civil rights movement. But back at home almost a month later, as representatives of civil rights, religious, labor, peace, women's environmental and elderly groups meet to chart their futures, few leaders dare predict they'll stay together.

"I'm not sure the cohesion is there. The situation is tenuous now," says State Rep. Saundra Graham, chairperson of the Massachusetts Twentieth Anniversary Mobilization, which organized the march and hopes to organize a united front of progressive groups from it. Nationally, the march's organizers have called for a "New Coalition of Conscience" to "provide a catalyst for powerful and much needed social changes in this nation." Last week Graham and a steering committee of interest groups met to evaluate the march and decide whether to fund a local coalition.

Such an alliance could mean a lot. For one thing, it could target legislation for heavy lobbying; already, in Congress and the State House, bills have been identified for possible support in areas ranging from El Salvador to fair housing to making King's birthday a holiday. Where lobbying fails, a coalition could call formidable protests in the street.

BUT SO FAR the biggest battles have been internal. Organizers point to troubling tensions: civil rights groups cite unions for opposing affirmative acion; unions say environmental and anti-military groups are insensitive to unemployment: peace groups have a reputation for being white, middle class and exclusory: conservative Black churches oppose abortion and challenge gay and lesbian participation. Even before last Thursday's evaluation meeting could begin, a debate erupted between the National Anti-Racist Organizing Committee and the American Jewish Congress over the war in Lebanon. Charges that Zionists are racists and civil rights and peace activists are anti-Semitic don't polish the image of the coalition movement.

There were other complaints. Not enough effort was made to reach Hispanics, organizers said. Churches, often the key political units in poor. Black neighborhoods, didn't mobilize enough marchers. The middle-class Urban League wouldn't dirty its hands in protest politics. The national organization was poor. Ultimately the steering committee postponed a decision on staying together and planned more meetings for Wednesday and next week.

"I have to say I was some what discouraged at the outcome of the meeting." Tony Palumba of Mobilization for Survival, a coalition of peace groups, said last week. "There was no energy, no enthusiasm to put differences aside. Someone walked in about halfway through and said. "Has anyone said anything nice about the coalition? And no one had."

In one sense the coalition is an inherent contradiction for these groups. Special interests abandon conventional party politics when they feel the political consensus does not respond to their needs. Interests become movements because compromise isn't enough: their proponents want to elbow their issues onto the national agenda. Taking the cue from civil rights, they establish their own organizations, constituencies and power bases.

That autonomy is hard to give up. "The fear is that this coalition will be just a forum for the Democrats and a rebuilding of the old coalition of liberals, labor and civil rights activists," Palumba says. Movement politics entail confrontation, not compromise.

SUCH DISSENSION, of course, is exactly why opponents don't take shows of strength like the August 27 protest too seriously. The Left, its critics claim, has become an ideological hash house serving special interest view. Another demonstration only demonstrations its discord. The American consensus, as articulated by a master rhetorician, equates liberalism with-bureaucracy and advises us the old answers are no solution.

But outdated answers don't define the Left. Persisting questions do. Over and over again those questions found voice at the Lincoln Memorial in an ever-growing community of discontent. And there was a new urgency in those voices, drawing not from extremism but from legitimacy: "Vote 84," read an old man's crudely-lettered sign. "Reagan must be stop. THE MAN IS SICK." Only 20 years after the 1963 march, this man could cast himself as the conserves, and a Republican as a radical fanatic. There is confidence in his assertion, a sense of political entitlement, hard won.

"I've been to a lot of rallies, let me tell you, a lot of rallies," Palumba says. "And this was special. Families, yes. And I noticed the elderly there. People dressed for church. And you're not going to see many [marches that are] multi-racial... It was amazing."

There is a special legitimacy to the civil rights movement, mother of the old New Left crusades. Part of it is that broad base, across race, economics and age. Part, too, is the index of conscience the movement provides; the most tangible, immediate injustice of racial inequality eclipses more abstract causes.

The anti-racist movement, as weak as it has been in the last few years, is probably the only one with the capacity to get everybody out." Ty dePass, a member of the Boston steering committee, says. The anniversary march offered the Left its identity, a sense of place and history. And if people are unsure where the Boston coalition is going, says Palumba. "They are very clear, real clear, where it is coming from."

ON AUGUST 27, there was no King to marshal the participants or to articulate their goals. They replayed his speech. Droning speakers told of their own dreams so often they could have been in psychoanalysis. Someone even did an impression of his voice. No one replaced him.

But like the old man with the sign, this crowd showed its own personality and direction. The name of Reagan made them roar when rhetoric didn't. King hadn't the political consensus in 1963, so he appealed to deeper religious and moral codes to show up the backwardnes of the segregationists. Now the political momentum is there. Twenty years later this crowd was incesed, not just inspired. King's successors both in Washington and Massachusetts have a stronger base to start with--if only they pull together.

The groups that comprise the Left rejected party politics for movement politics because the old Democratic coalition had promised much and delivered little. Now these groups owe their own constituents a new pragmatic coalition--or at least the search for one. The August 27 march should tell them that while group leaders, argue, their constituency grows. Their mandate wells up from the needs of mistreated Americans and will grow as long as government fails to grant them a fair chance.

Will the movements meet that mandate? Palumba gives the Boston coalition a 50-50 chance of being born, and an even smaller chance of proving meaningful. But the would-be coalition squabbling at the Statehouse tomorrow and next week should remember the 250,000 who gathered without King. Before they bicker and lose the moment, they should remember the maturity and power in that crowd--in its peacefulness, its determination, in the advice of the mother who said. "You won't get lost today. We're all walking the same way, and we'll all get there together."