ONE HAS THE sense that this Saturday's "March for Jobs, Peace and Freedom" is a test of sorts, and that the organizers have taken exciting risks. But a test of what? And what will constitute success?

Possibility 1: Will the march focus the nation's attention on an unappreciated problem? In 1963, still too few Americans felt touched by the tragic dimensions of discrimination or caught up in the imperative of racial justice. A snail-like Congress and a timid president needed prodding. That summer's pilgrimage was for an awakening. In contrast, the marchers' agenda now includes familiar and hotly contested matters of economic policy and world peace. The speeches are unlikely to make the problems of unemployment lines or single-parent families seem as morally compelling as church bombings or Bull Connor's malevolent swagger; few onlookers will have a revelation. So this march won't succeed as a call to consciousness.

Possibility 2: Nor is the march's substantive message extraordinary. The platform is essentially the familiar one of minority and liberal leaders, a mixed bag of sensible proposals and pipe dreams, not a new agenda. The tone of the message attempts the visionary, but recent years suggest that in falling short, the message will not persuade. There is little news, or accomplishment, in stitching together another set of proposals that at best represent another incremental evolution of the liberal policy strategy. The only qualification is the wedding of traditional domestic civil rights concerns with the so-called peace movement. There's been a common law marriage since black leaders followed Dr. King's early example in questioning the Vietnam War. Now-- for better or worse--it's official.

Possibility 3: No surprise either that over 700 organizations have endorsed the march. Of course there is a sizable constituency on general themes. But broad verbal participation in a coalition, with varying degrees of enthusiasm, doesn't demonstrate political effectiveness, which is the important question today.

Yet the march is significant. It is a memorial to a man, and the anniversary of a special moment in a movement of exceptional importance in the nation's modern history. And it is a reminder of the unfinished business and the possibilities ahead. In these respects, success is certain. But also, consider: prisoners in the Leavenworth Penitentiary raised over $500 to help pay the expenses of a group of elderly Kansans coming to Washington this week. There were weekly fish fries in Durham to raise money for buses. Local groups have been recruiting marchers in a list of cities and towns that reads like a gazetteer: Selma and Peoria; Albany, Ga., and Albany, N.Y.; Teaneck, N.J., and Moss Point, Miss. The organizers expect 3,000 buses and over a quarter of a million participants. Countless people who attended the 1963 march, perhaps as children, are planning to return because they feel part of a thread in history's weave and don't want it broken. The important test for the march is not the platform or the rhetoric, but the breadth of the organizing and participation, which indicate the potential for the future. At its best, therefore, the march may signal an incipient, widespread resurgence of commitment. Only time will tell.

There will be lesser dramas. Jesse Jackson's speech will be compared with that of Martin Luther King. The peace theme and the economic protest may compete rather than resonate. There will be people and particular organizations represented whose interests are cynical and manipulative and out of keeping with the dominant spirit of the day. Black leaders will bask in a fleeting unity with organizations increasingly committed to other struggles. Yet this family renewal of a memorial and anniversary is momentous, and much needed. The important questions are whether it contains the seeds of an important change in the life of the nation, and whether the organizers know how to use the troops they have called to march.