Visiting South Africa recently for the first time in 14 years, I was struck by the changes that have occurred in the public manifestations of apartheid, particularly in the areas frequented by visitors. In Johannesburg, for example, a short-term visitor might be forgiven for thinking that apartheid was dead or dying. This thinking would not last long, however, after the visitor got outside the city center into the townships or after he met with the people who are engaged in the very difficult task of fighting apartheid with its new, improved camouflage.

The fact is apartheid is alive and well in South Africa, and the changes so far promoted by the genial President F. W. de Klerk do not even begin to touch its essence. The people of the Soweto and Alexandra townships outside Johannesburg -- many living in abject poverty worse than most refugee camps I have visited -- know that apartheid is alive and well. The migrant workers living 12-plus to a room in their drab, soot-covered, all-male hostels built in the middle of nowhere could tell you the same. So would African National Congress and United Democratic Front activists who are busily trying to rebuild and strengthen political structures knowing full well that the government could change direction any day and crack down on them. After decades of a largely underground existence -- and with many of their key leaders still exiled -- theirs is not an enviable task.

Their task is being made more difficult every day as de Klerk skirts around the edges of apartheid teasing primarily the international community with seemingly monumental changes. They know that many of his actions are well calculated to divide the opposition and preserve white minority domination. They cite the continuing conflict in Natal, where government forces are firmly allied with the Inkatha movement in a desperate effort to preserve the myth that Chief Buthelezi is the leader of the Zulus. They point out that recent pronouncements about desegregation of public facilities such as hospitals are meaningless, since the government quietly refuses to provide the funds needed for the desegregation.

In spite of these tremendous difficulties, these activists are infused with enthusiasm and confidence. They are convinced that they have the leadership which, with a little bit of help from the international community, will lead South Africa into democracy.

Clearly, one of their biggest assets is Nelson Mandela, who has pursued an unrelenting schedule since his release from prison last February. Like many who have spent some time with Mandela, I find it difficult to convey fully his unique capacity to engender trust and confidence. Americans who will soon meet him up close are going to be treated to a special kind of political leader: thoughtful, principled, direct, and humble almost to a fault. His speeches will be a surprise to Americans accustomed to high-decibel emotional rhetoric and simplistic sloganeering.

In my discussions with Mandela and other prodemocracy leaders, I was most interested in their assessment of what it would take to advance the process of change in as peaceful and rapid a manner as possible. I also wanted their candid assessment of de Klerk.

Mandela and the people I met with were firm in their call for the continuation of sanctions. In fact, they were quite concerned that speculation about imminent relaxation of United States or European sanctions could derail negotiations. They believe that precipitous action to weaken Western sanctions, particularly moves by the United States, would plunge South Africa into a deeper crisis. International sanctions clearly are a very important bargaining chip for the prodemocracy forces. Without irreversible changes that would occur only after the repeal of the basic laws of apartheid, tampering with current sanctions would be irresponsible.

ANC and UDF officials were quite disturbed that many in the international community have been eager to exaggerate de Klerk's role in the changing situation in South Africa. Not enough credit is being given to the work of activists and the sacrifices of the people of South Africa. Mandela pointed out that in many cases, de Klerk was proposing legislation that simply affirmed changes that had already occurred. This is particularly true in terms of the separate amenities and the group areas acts. Governmental actions in these areas are essentially belated acknowledgments of changes forced by the people. Proper recognition of this dynamic is essential to the conduct of a sensible American policy toward South Africa.

Mandela's visit this week will provide the United States with an excellent opportunity to demonstrate our support for the positive role the ANC and the UDF have been playing in South Africa. Our affirmative response to any request he might make for governmental or private assistance would go a long way toward making amends for our role in the perpetuation of apartheid.

Certainly, the ANC needs material assistance. The democratic process in South Africa needs support. The surest way to reduce the likelihood of violence is to assist the ANC in its efforts to build regular political structures throughout the country. We have given hundreds of millions of dollars to encourage democracy in Europe and Latin America. If we move now with imagination and dispatch, we could help change the terms of the struggle in South Africa, moving it firmly into the arena of democratic politics.

De Klerk, according to most of the activists with whom I spoke, seems committed to changing the cruder aspects of apartheid. It is far from certain, however, that his commitment extends to the building of a truly democratic society with the certainty of black majority rule. In any case, it would be reckless to depend on his sincerity. The possibilities for a reversal must be removed from his purview. The way to do this is to strengthen the South African democratic forces while maintaining the pressure for change on the government.

This was the message I received in South Africa and the one that Mandela will bring to the United States.

The writer is executive director of TransAfrica, a lobbying organization. He is helping to organize Nelson Mandela's trip to the United States.