The voice of America sometimes can be comT pared to what writer James Weldon Johnson once said about the voice of the Southern black preacher: It can range from a whisper to a mighty clap of thunder. A case in point was Solidarity Day. Americans chose to raise voices too long silent, because this time, backed against the wall, they had had enough.

On the face of it, the sheer numbers of those who participated -- 260,000, at latest estimate -- would seem to promise a real thunderclap, one heard in the farthest corners of the nearby White House. But, in fact, it could have been perceived as something quite different.

Part of the problem is that marches no longer have the impact they once had; unquestionably, new creative approaches are demanded. Another problem is that federal ears seem deaf to marchers -- witness the case of the ex-CETA worker from Harlem who came to Washington to remind government leaders that babies in his community still are being bitten in their cribs by rats.

It also may be that Republicans march to a different -- and decidedly dogmatic -- drummer that would ignore such a voice anyway.

But there is another factor to consider, too: the marchers' own perceptions. For even though the protesters carried placards which often bore differing messages, they were united in their demand for answers befitting complex questions. Yet they received in reply nothing more than a chorus of inflexibly pat solutions.

Some anticipated this and avoided the Mall on Saturday. They feel just as passionately that Reagan's economic policies give to the greedy and take from the needy and that the country is cruising for an economic bruising. Saturday morning I called one man I know who feels this way (I expected no answer at his home). He picked it up on the first ring and his voice was angry.

"I've had it with marching," said this battle-scarred veteran of civil rights marches that include the 1963 march on Washington. "It ain't goin' to move one vote and Ronald Reagan doesn't give a damn. Besides, the money they're spending could be better spent helping the people getting chopped by Reagan's cuts."

Later, en route to the Mall, I remembered that August day 18 years ago -- the emotional fervor and the drama of Martin Luther King's "I Have a Dream" speech. Some voices had recently been comparing that day with Solidarity Day. They saw that day as pivotal to setting into motion the events that propelled the civil rights movement into what it would become. These voices hoped Solidarity Day would set into motion a more assertive lobbying effort to give greater presence to the Reagan resistance movement.

But I did not find on Saturday the emotional, almost radical fervor of the March on Washington. Saturday's voices were bruised, not strident. Because many had voted for the man whose policy they now protested, their song was more "You've done me wrong" than "Let a new day of justice arise."

To their "We Shall Overcome," Ronald Reagan sang, "Ain't going to let nobody turn me around."

So the question must be asked: Did 260,000 people come for nothing? Was my friend right in thinking the money could have been better spent helping the Harlem babies who must duck rats in their sleep?

My answer is that the people who raised their disparate voices together Saturday reinforced each other. When they were divided across America, Ronald Reagan could, in the isolation of the White House, declare that he had a national mandate. But when the protesters boarded buses and rode from Cleveland and California, Pittsburgh and Peoria, the mandate melody became a suspect refrain.

Saturday, I asked one woman who had stood patiently listening to the speeches and to the voices of others in the crowd around her how she felt about it all. She was a black woman and her particular cause was the extra pain blacks would feel from Reagan's economic and social policies, thanks to having been systematically denied equal opportunity for so long.

"Today is good," she began, "but it is a white, conservative show. The high point for me was the speech by Benjamin Hooks of the NAACP, not because he was black, but because he was so emotional and compassionate. I felt more."

But in coming together with the marchers, she had confronted their issues as well as her own. And while Solidarity Day did not altogether "take" on her, she left with recharged batteries, saw old friends, compared notes and battle scars.

I had gone to see if Solidarity Day might be the formation of a new cutting edge of resistance, a blending of the voices of protest. Those voices were heard, and across the nation a lot of people feel better today for having spent the weekend in Washington. But if Solidarity Day is to be more than a picnic, more than a songfest, if it is to be the birth of a resistance movement against Reaganomics, the disparate voices of the marchers will have to unite much more in a common cause.

This will take organization, true cooperation, compassion and coalition building beyond anything this country has experienced in the past. Only if the once-silent voices raised for a moment on Saturday can truly harmonize will they sing with the strength -- the clap of thunder -- it will take to move Ronald Reagan, even if he is horseback riding as far away as California.