The protests of the Free South Africa Movement have prompted some to a mixed assessment: They are a good thing, but they are essentially symbolic gestures that will not ultimately accomplish much in altering the apartheid system.

If this proves true, the protests then will only reflect three decades of U.S. policy to a country that deeply offends American sensibilities of justice, yet exerts a strange fascination on us because of an almost family resemblance in its life- style, aspirations and problems.

Whether Republican or Democratic, U.S. administrations since the 1950s have voiced criticism of apartheid but done very little to stop a process that has created a nightmare both for its victims, the blacks, and for those few far-seeing whites of South Africa who want to reverse it, but don't know how or don't have the power to do it.

Something often forgotten is that just 30 years ago South Africa was not the repressive, controlled and polarized society that it is today. That process began in 1948 -- a mere six years before the Supreme Court's Brown v. Board of Education decision launched our civil rights movement -- when the National Party, the vehicle of Afrikaner nationalism, won control of the government.

At that time, South Africa's legal system recognized habeaus corpus. That prerequisite of political freedom no longer exists because of security laws allowing indefinite detention incommunicado.

In the 1950s, it was still possible for blacks and whites to hold political rallies, marches and demonstrations. It is now against the law to rally, march or demonstrate, and political parties cannot include members of different races.

In the 1950s, the grand apartheid system, which breaks up the beautiful country into 10 tribal homelands and "white" South Africa, was more a scheme on government drawing boards than a reality. Today, all of those homelands have defined boundaries and their own bureaucracies set up by Pretoria and run by blacks. None of the homelands, which together comprise just 13 percent of South African territory, includes any major industrial or urban area. Four of them are already "independent," and the government intends that all the others will become "independent."

In setting up the homeland machinery, the government has and continues to uproot more than 3.5 million blacks from their homes, forcing them to relocate in the already overpopulated homelands. One can only wonder at the challenge any future government in South Africa faces in redistributing the land and its resources after taking most of it away from blacks and giving it to whites.

And back in the early 1950s citizenship was not an issue. Today citizenship is the central issue. Blacks maintain they are citizens of South Africa and therefore entitled to national voting rights. The white government's policy says blacks must be citizens of one of the 10 homelands (even if they have never lived in one) and exercise their "national" voting rights there.

In short, while the Afrikaner has transformed South Africa into a juggernaut with a military and economic hegemony in the region that any beleaguered country could envy, at home he has boxed himself into a corner.

Current moves to alter the complexion of the central government by bringing in Indians and Coloreds, or persons of mixed race, do not address these central issues of political freedom and citizenship. That is their basic flaw. Though the Afrikaners say this is the beginning of an evolutionary process of change, they have never publicly stated the goal of that proc closest they have come to that is to say that, perhaps, in another generation, the black homelands through their elected leaders may join a new overall body with the leaders of "white" South Africa. That is a far cry from the aspirations of black South Africans.

So what can the U.S. government do apart from sit on the sidelines and say uncomplimentary things about Pretoria? There are those who say that despite their zeal to be considered a friendly ally of Washington, the Afrikaners do not respond to pressure, be it economic, political or verbal. This is true -- in the short run. The United States has never, except during the Carter administration, exerted much pressure on Pretoria.

Much of the current discussion set off by the Free South Africa Movement centers on economic sanctions and disinvestment by U.S. firms and financial centers. The history of economic sanctions to produce political change is not that sterling.

White-run Rhodesia withstood international economic sanctions for 15 years -- and prospered while doing it. The lesson of Rhodesia is that the transformation to Zimbabwe came only when Britain, encouraged by the United States and concerned over an increasingly internationalized black guerrilla war in Rhodesia, bit the political bullet and forced its rebel colony to capitulate.

Much more than economic pressures have to happen before the U.S. government can hope to influence events in South Africa. And that is the harder, task because it requires foresight, planning, political will and large doses of skillful diplomacy. In short, it needs the kind of long-view approach usually associated with such top foreign policy concerns as arms control.

There is nothing intrinsically wrong with the concept of "constructive engagement." It's the implementation that has gotten the present administration into hot water. A "constructively engaged" relationship between Washington and Pretoria really aimed at change ought to start with some tough talk to the South Africans about the daunting task of reform they have before them.

It must be made clear that the U.S. government does not intend that South Africans accomplish the task alone but that it intends to help them to do so. The Afrikaners also need to be told they cannot be the sole arbiters of the pace of change in South Africa. They must open a dialogue with black leaders. They must be forced to concentrate on the central issues and to apply their ingenuity -- which helped them acquire the technology to build an atomic bomb -- to the urgent task of domestic survival.

American diplomats faint at the suggestion that they offer a blueprint for domestic reform to a sovereign country. But that does not mean there cannot be sincere, hard-driving, on-going talks at high levels on the process of change in South Africa and what its end product will look like. The first need is to get rid of the ambiguity in the U.S. attitude toward South Africa. The United States should make clear to the South Africans and to everyone else what principles that end product should involve and without which the United States will not bless South Africa's reforms. National voting rights, citizenship, land ownership, a restoration of habeas corpus and political freedoms ought to be some of those principles.

The United States should also begin building an enduring, visible relationship with South African blacks and their leaders. Those leaders are many and varied. If there is to be peace, all of them must be considered, including the African National Congress. Despite its banning in 1963 it has widespread support inside the country. But because the United States has largely ignored it, the Soviet Union has become its main backer by default.

The task of helping South Africa change, if the United States decides it wants to do this, is not a task for only one administration -- it needs planners who can think in decades, planners who can use the past three decades of U.S. policy toward South Africa as an example of something that is much less than perfect.