SECRETARY OF STATE Cyrus Vance announced last week that the Carter administration will move to repeal the Byrd amendment, which allows U.S. companies to buy Rhodesian chrome in defiance of the U.N. boycott of the southern African country. At this point, the gesture would be little more than symbolic. The U.S. does not need the chrome--Rhodesia supplies less than ten per cent of this country's needs, and the government here has stockpiled enough for almost a year anyway. The effect on Rhodesia, while real, would merely be yet another blow to an economy that has been slipping rapidly over the last two years.

Nevertheless, the repeal of the Byrd amendment could signal a new phase in the politics of southern Africa. The negotiations between Rhodesian Prime Minister Ian Smith's white-minority government and leaders of the black nationalist movement became deadlocked last month, and no one seems sure of the direction events are going to take. Smith's feelers toward moderate blacks may result in a black-white coalition if Bishop Muzorewa or Reverend Sithole accept the offers; but none of the three have control over the Zimbabwean freedom fighters, whose leaders have said repeatedly they will not accept a transition government in which the whites remain in control of the country's armed forces. And Smith continues to demand that transition phase, which means that future negotiations, like those that died in Geneva last month, are likely to reach a stalemate.

It was in recognition of Muzorewa's and Sithole's impotence that the leaders of 21 African countries endorsed the more radical Patriotic Front, a coalition of Zimbabwean nationalist groups committed to complete majority rule in Rhodesia. Early this month, the Secretary General of the Organization of African States said bluntly, "Now that a peaceful solution has failed, we have to intensify the struggle, and the Patriotic Front is the only one fighting. So we support the Front." There are 6.2 million blacks in Zimbabwe, compared to a shrinking population of 270,000 whites. A coalition government that allowed the tiny group of whites to dominate the country would be little more than a cosmetic change, and the freedom fighters are unlikely to accept Smith's solution.

THE QUESTION, of course, is what happens next. Since the fighting began in Rhodesia in 1972, at least 3534 people have been killed. The government reports that 847 of the dead were black civilians, 71 of them white civilians, and 252 government soldiers. The figures are suspect--Smith's soldiers do not seem to be too careful about distinguishing between black civilians and black insurgents--but clearly people are dying. Last week, 96 people died, one of the worst weeks of the war.

And the fighting is destroying the already floundering Rhodesian economy. Of a white labor force of 90,000, about 10,000 serve in the army or the police; this has placed a severe strain on industries that rely on skilled whites. Almost a third of the Rhodesian budget goes for defense purposes. And perhaps most important in a country geared to production for export, Rhodesia's exports have dropped off sharply. Zambia and Mozambique have closed their borders completely, and South Africa has begun to slow traffic from landlocked Rhodesia. At this point, it would be more surprising if Rhodesian businessmen did not try to negotiate for a settlement than if they did.

But J. Nkomo and RoberMugabe, leaders of the Patriotic Front, refuse to negotiate further with Smith's regime. Mugabe has said repeatedly that the Front will not compensate whites who lose their property in a free Zimbabwe, and Rhodesian businessmen view the Front as a much greater threat than simply giving blacks the vote. There appears to be no common ground for negotiations. The situation is beginning to look like the one that developed in Angola just before and after the Portuguese left: one group of blacks promising a moderate government supported by the western capitalist world, pitted against another, much more radical group refusing that support.

The U.S., then, is stepping in at a critical juncture. There is no longer any question that there will be some kind of majority rule in Zimbabwe. The issue that remains is the form that government will take. Muzorewa and Sithole seem willing to settle for a capitalist structure allowing U.S. and other multinationals to retain their control of Rhodesia's economy. While the ideology of the Patriotic Front is a little unclear, it seems at the moment to be heading in a socialist direction. The Front has accepted support from the Soviet Union, but without some support the freedom fighters could not hope to overthrow the white regime. And the U.S. is not likely to permit the Front to nationalize American businesses in Zimbabwe without offering other alternatives. Vance's effort to repeal the Byrd amendment, thus assuring the black nationalists that the U.S. supports them in their negotiations and is friendly to their cause, is a natural step to opening communication with the freedom fighters.

WHEN ANDREW YOUNG was in Africa last month, he proposed a new series of negotiations between Zimbabwean leaders, the five front-line states bordering Zimbabwe, Zaire, Nigeria, and the U.S. Smith's regime was entirely ignored in Young's proposal, a clear recognition that the real split is between the Zimbabweans, not between whites and blacks. The proposal has not been accepted yet, but it does not bode well for the future of a socialist state in Zimbabwe. Both Zaire and Nigeria--who have been excluded till now from negotiation proposals for Zimbabwe--are heavily in debt, and most of their debts are held by American banks. The U.S. evidently hopes to play a much larger role in Zimbabwe than in the past, and that role is likely to be based on an effort to shape the kind of government that takes control in Zimbabwe rather than answering the people's needs.

And to the south remains South Africa, whose presence makes any American move in Zimbabwe suspect. The economic and military interests of the U.S. in South Africa are closely tied to the preservation of some kind of stability, and a radical government in Rhodesia would probably threaten the white South African regime. If the U.S. can push the Zimbabweans to compromise position, American interests in South Africa will be much safer than if a radical Zimbabwean regime shelters South African freedom fighters just as Mozambique shelters the Zimbabweans now. Such a haven for guerrillas would increase the likelihood of a violent struggle threatening the smooth functioning of South Africa's mines and industries.

Carter's administration seems to be searching for a new policy in southern Africa. Vance and Young are not suggesting the Kissinger style of shuttle diplomacy, and they are willing to recognize the freedom fighters' rights to their country. But it will take more than symbolic gestures to persuade the people of Southern Africa that the U.S. hopes to play a positive role in their countries; repealing the Byrd amendment would be only a small step toward a real change in American foreign policy.