It is now clear that the past four years of "constructive engagement" with South Africa has had very destructive consequences -- both for South Africans and for American national interests. But the Reagan administration now has a unique opportunity, if it will only seize the initiative, to fashion a new approach toward South Africa that will enjoy genuine bipartisan support within Congress and broad-based support from the American public.

This new opportunity is presented by the convergence of three separate developments. First, in South Africa itself an unprecedented political mobilization is occurring in response to both the intensification of repression by the South African army and police and the recent constitutional changes designed to further entrench the white minority regime. In the past several months, nearly 200 black opponents of apartheid have been killed, 1,000 have been injured and more than 3,000 have been arrested, many under draconian security laws that permit indefinite detention. A large percentage of those arrested have been children under the age of 18.

Two large national opposition bodies, the United Democratic Front and the National Forum, waged a successful boycott of recent "non-white" elections, and their campaign against the new apartheid constitution is continuing. In November, black unions staged the largest workers' strike in South African history, prompting a massive government crackdown and witch hunt directed against the strike's organizers. But the black labor movement has already demonstrated its vastly expanded potential for political as well as economic action.

Second, in our own country there is an increased public awareness of the viciousness of apartheid, and U.S. policies toward the white minority government have become increasingly salient to a broad cross-section of American voters. The current highly visible direct-action campaign represents the culmination of years of activity by state and local legislatures, university students, anti-apartheid organizations and churches. The Free South Africa Movement has captured the imagination and attention of the media with its peaceful demonstrations throughout the country, and the resulting national coverage has produced an equally unprecedented and sorely needed public involvement in the foreign policy debate.

Finally, last week's letter from conservative Republicans in Congress to the South African ambassador demanding that steps be taken immediately to dismantle apartheid underlines the widespread bipartisan discomfort, within Congress, with the policy of "constructive engagement."

But two things must happen if the administration is to effectively exploit the new opportunity for shaping a new bipartisan approach to South Africa.

First, the administration must recognize that "constructive engagement" has in fact failed; more important, it must understand why. The policy of closer association with South Africa has been justified as a means of preventing violence and encouraging peaceful evolutionary change. But when, in the name of "quiet diplomacy," our ambassador to the United Nations uses the American vote or veto power to block or to abstain on resolutions condemning South African aggression, or when our government remains conspicuously silent in the face of South African government atrocities, or when high-level administration officials publicly defend the recent constitutional changes in South Africa as evidence of forward movement, or when the administration refuses to consider even the most modest of economic sanctions frequently used against other countries, we only invite greater violence. The real message conveyed to South African authorities is that they now have a much freer hand to do what they will. Under this "all carrots -- no sticks" policy, the Afrikaner regime knows, in advance, that there will not be any real cost imposed on South Africa, no matter how many black trade union leaders are imprisoned or tortured, no matter how many black communities are terrorized by massive army search-and-seizure operations, and no matter how many people are killed by South African police.

Second, if we are to develop a genuinely bipartisan policy toward South Africa, the administration must be committed to before-the-fact consultation and continuing cooperation with Congress. The key to a sustainable and effective foreign policy, in any area, is the development of a Congressional consensus solidly in support of that policy. We are now rapidly developing such a consensus. The new congressional assertiveness should therefore be seen not as a threat to the president's leadership but as an opportunity for the administration to develop, with congressional and public support, an urgently needed new South African policy. The challenge that faces both the administration and Congress is to develop an alternative to "constructive engagement" that will be truly consistent with both American values and American national interests. In my view, the American people are telling us that those two objectives can and indeed must go together.

Clearly, the American people are making the struggle for human dignity in South Africa their struggle. Can we ask anything less of the American government? If our own national commitments to justice and full racial and civil equality are to prevail, we must disassociate ourselves from apartheid by any means necessary and simultaneously clearly associate ourselves with the struggle in South Africa to achieve a nonracial democratic society. Bishop Desmond Tutu has said, "You can't change apartheid by collaborating with it." Black and white Americans together must pay heed to Bishop Tutu's words so that we will not increasingly become party to an evil blight that causes oppression and suffering among millions of our fellow human beings.