The Carter administration, which took office committed to reducing the Cold War focus of U.S. policy in Africa, has reversed its rhetoric and substantially revised its operations there in recent months.

As U.S. Air Force planes prepare to land African troops in Zaire's ravaged Shaba Province this weekend and lift out French legionnaires, the Washington policy establishement, as well as the world outside, is watching diligently for signs of how much further the change will go.

In the past several weeks, the emerging Carter policy of emphasizing and counteracting Soviet and Cuban activities in Africa has set off instense controversy involving high politics, personal animosities and, at a basic level, differences of view about international priorities, East-West relations and the U.S role in far-off military conflicts.

Starting with dramatic airlift of Cuban troops and Soviet supplies to Ethiopia late last year, communist operations in Africa have been a growing preoccupation of major elements of the Carter administration. Until recently the U.S. reaction was primarily diplomatic and verbal. But a National Security Council study of the Soviet-Cuban problem scheduled to be completed in the first draft a week from now, recent soundings with Congress and the dispatch of Air Force transports to Zaire raise the prospect that the administration may decide to take stronger action.

The administraion contains high-ranking officials who say they are deeply troubled by President Carter's apparent new willingness to involve America more deeply in African conflicts. These unhappy officials tend to ascribe much of the change in U.S. behavior to the efforts of Zbigniew Brzezinski, Carter's national security affairs adviser, who has expressed concern about Soviet-Cuban involvement in Africa virtually since Carter's inauguration.

Just in the last few days administration officials have been arguing - sometimes emotionally - about how big a commitment the United States should make to a multinational African military force being organized to help Zaire defend Shaba Province from Katangese guerrillas.

In view of the increasingly poisonous nature of the Soviet-American dialogue, decisions by Moscow or Washington or both to raise the ante could bring about more dangerous confrontations in Africa. This possibility concerns many U.S. policymakers who are deeply worried less about what has happened than about what the trends imply and what may happen.

While campaigning for the presidency. Carter critized the Ford administration for "fueling the East-West arms race in Africa," and said the Soviet-Cuban presence in Angloa was "regrettable," but it "need not constitute a threat to United States interests."

Once elected, Carter installed Andrew Young as the U.S. ambassordor to United Nations with special responsibility for Africa, the first black to have strong influence on U.S. foreign policy. Young quickly established a new tone and direction to American policy in Africa, one applauded by black leaders on the continent.

Last July 1. Secretary of State Cyrus R. Vance gave a major address seting down the new administraion's basic policy for Africa. In contrast to the late-blooming Kissinger activism in the Ford administraion, Vance emphasized the importance of "affrimative policies" and declared that "a negative, reactive American policy that seeks only to oppose Soviet or Cuban involvement in Africa would be both dangerous and futile."

The essence of the 1977 policy was to deemphasize the East-West confrontation in Africa, stress U.S. support for African nationalism and economic development, and bring much stronger U.S. pressures to bear against white minority rule in Rhodesia and South Africa.

When Katangese forces based in Angola invaded Zaire's Shaba Province in March-April 1977 an episode now known as Shaba 1), the United States officially maintained it had "no hard information" to comfirm President Mobuto Sese Seko's charges that Soviets and Cubans were involved. The United States rejected Mobutu's request for weapons and sent only "nonlethal aid". A White House spokesman said," We do not see the (Shaba) situation as an East-west confrontation".

Referring to this episode in his July 1 policy speech. Vance declared that "when such crises as the recent invasion of Zaire arise, we see no advantage in unilateral responses and emphasizing their East'West implications . . . As President Carter recently said, it is best to fight fire with water".

Testimony by Vance in closed session to the Senate Foreign Relations Committee's African subcommittee three weeks ago provides vivid documentation of the policy evolution. While support for African nationalism, economic development and majority rule are still part of the program, about half of Vance's May 12 presentation concentrated on the Soviet-Cuban challenge on the continent and the U.S. "strenuous effort" to counter it. Specifically, Vance outlined:

New U.S. military aid or new authority for military aid to Sudan, Chad, Kennya and Zaire. (Since then, the administration has, in addition, taken steps toward the supply of "defensive" arms to Somalia)

Public and private representations to the Soviets and Cubans that "we view their willingness to exacerbate armed conflict in Africa as a matter of serious concern."

U.S. warnings to the Soviets that their activities in Africa pose "dangers . . . for our overall relations (Brzezinski had publicly been more explicit in warning that events in Africa could jeopardize a strategic arms limitaion agreement)

The Secretary did not mention two other elements in the new policy that have emerged more clearly since that last testimony - consideration of indirect reinvolvement in Angola's support first for French and Belgian and now African mulitary forces in the troubled Shaba province.

Sitting in a White House office Friday afternoon, one of the chief architects of the shift in emphasis declared simply: "Events imposed it." In his perpective, the communist side, rather than the United States, has injected the Cold War into Africa and it is necessary for the United States to respond. "By not meeting the Cuban-Soviet challenge soon enough, it would be more difficult to meet it later. And in domestic terms we could be charged with trying to ignore it," he said.

And important White House aide just below the top policymaking level amplified. "You really have a different situation from last summer. There has been a boubling of Cuban combat forces, mostly in Ethopia, and more than $1 billion in Soviet military equipment pumped in. There is a more expansive Soviet and Cuban presence."

A senior State Department official said that after the experience in Ethopia, the United States had to assume that - in the absence of countermeasures - the communist forces will be prepared - to move on to the explosive black-white conflicts of southern Africa. That would mean Soviet-backed Cubans in Rhodesia in the near future, a prospect so ominous to the administration that its top priority now is to avoid it.

On the other hand, a skeptical congressional source deeply involved in African matters maintained that Brzezinski and those anxious to emphasize anticommunism are not looking at Africa but "looking at the Soviet-Cuban problem." During the Ethiopian-Somalia war over the the Ogaden region, according to this source, Brzezinski was heard to say, "The problem isn't the war, the problem is the Soviet and Cuban presence." But Brzezinski seems never to have considered, the source continued, that the war was what made the Soviet-Cuban presence possible.

A State Department official who closely monitors Africa policy attributed the shift in emphasis to a combination of Brzezinski's inherent anticommunist and global concerns and U.S. sensitivity, bordering on irrationality, about the activities of Cuba. It is not yet clear how far the president has come in his thinking, said the official. "We don't know if we're back into the 1950s until hard decisions are made on a variety of things."

The Soviet Union and Cuba have long term been involved in the affairs of Africa, but the meshing of Cuban combat troops and Soviet logistics and arms - thousand of miles from the national territory of either state - is an unexpected development of major importance. This combination first appeared in Angola late in 1975, and the Ford administration's efforts to counteract it were halted in early 1976 by act of Congress.

When the Carter administration came to office, about 22,000 Cuban troops or advisers were reported in Africa, 17,000 of them in Angola. For Carter and most of his new team, the Soviet-Cuban force in Angola was considered a mismanaged affair of the Ford administration and essentially a problem of the past. Since then, the Soviet-Cuban force in Africa has roughly doubled to about 43,000 troops.

The Soviet-Cuban airlift into Ethiopia, which began Nov.28, posed the challenge in sudden, sharp and extremely difficult fashion for the Carter administration.

The United States faced the agonizing problem that the Soviet-Cuban force had been invited by a legitimate African government, Ethiopia, to do battle against invading troops from neighbouring Somalia! When Brzezinski and others considered military aid to Somalia, perhaps through third countries, to counterbalance the communist help, the State Department pointed out that such action would be denounced throughout Africa.

A Brzezinski plan to send a U.S. naval task force as a show of force of deter the Russians was reportedly opposed by Vance and Secretary of Defense Harold Brown. "If our bluff had been called, would we have been prepared to use the fleet? We had to make rigorous assessement of how important is that area to us as a nation," said an official involved in the discussions.

In the end, the Carter administration limited itself to publicizing the Soviet-Cuban intervention, obtaining statesment from the Soviets and Ethiopians that they would not cross the Somali border, and pressing other African nations to speak out against any extension of Soviet-Cuban force outside Ethiopian territory. "If you are deprived of dirty tricks or military responses, those are the sorts of things you do," explained a policymaker.

This sense of relative helplessness produced frustrations. By this spring administration officials began to discuss the now well-publicized allegation that Congress had unduly tied the president's hands in Africa. This concern led to a decision to explore some new alternatives within the administration and on Capitol Hill.

In late April Adm. Stansfield Turner, director of central intelligence, went to Sen. Dick Clark (D-Iowa) to discuss a plan to secretly sell weapons to France for transshipment to Angola for guerrillas fighting for the union for the Total Independence of Angola (UNITA). This aid could not be provided legally under an amendment originally introducted by Clark.

Turner said the administration would want to consult with a number of members of Congress before doing anything about the plan. More than consultations was required. Clark replied - the plan Turner was talking about would violate the law. Yes, Turner later agreed, the Central Intelligence Agency's lawyers had reached the same conclusion.

On whose instructions did Turner approach Clark? A source close to Turner said he had "clear authorization" from the Security Consultative Committee in the White House. An official who participated in recent deliberations of that committee said the idea was never discussed at its mettings. Brzezinski has refused to discuss suggestions that he had approved Turner's actions. Jody Powell, the President's press secretary, has said Carter did not know about Turner's visit to Clark until after it occured.

The rationale Turner offered Clark was that aid to UNITA rebels fighting the Angolan central government, heavily supported by Cubans, might tie the Cubans down there, making it difficult for them to consider moving into the Rhodesian civil war. A stronger UNITA also could inflict more damage on the Cubans in Angola. Raising the price for the communists in Angola is something Brzezinski " just kept toying with" in recent months, said an informed official.

But aid for the UNITA fight against the Angolian central government led by Agestinhe Neto also could disrupt a basic element in the African policy laid down earlier in the Carter administration by Young, Vance and their colleagues - the attempt to establish majority rule in Namibia, foremely Southwest Africa. That policy was to support the Southwest Africa People's Organization (SWAPO), which, in turn, was dependent on Neto in Angola. U.S. support for Neto's UNITA enemies could lead to a collapse of negotiations with SWAPO.

The plan Turner described has not moved forward. After press accounts in late May - three weeks after the fact - described what had happened, Carter said he had no desire to repeal the Clark amendment or to become involved in Angola.

But by that time the new Katangese invasion of Shaba had given the United States a clear opportunity to help France and Belguim to repel the invaders and protect Zaire's territority integrity. U.S. officials agreed speedily and, reportedly, enthusiastically to use American aircraft to transport French and Belgian forces.

It was an appealing opportunity to help a legitimate government defend against Soviet-Cuban incursions - if the communists actually were involved. And the Carter administration aggressively looked for and said it found evidence of Cuban involvement in the new Katangan invasion.

Cuba and the Soviet Union both charged that Carter was wrong, but the administration struck by its position and claimed that Cuba had repeatedly lied about its involvements in Africa in the past. Administration officials who read the three-inch-thick pile of intelligence documents that were basis of the charge of Cuban involvement disagreed about their persuasiveness. Some said they proved the involvement; others said they were ambiguous. The administration has declined to make the information public.

The French-Belgian intervention in Shaba had essentially succeeded in driving the rebels out of the province and resecuring the territory, but the administration recognized that this was a temporary accomplishment. A spirited debate began inside the administration over what to do next.

On May 26 Carter met with President Valery Giscard d'Estaing of France over dinner at the White House. They agreed that France and the United States would cooperate to help African nations protect themselves and each other against "destablishing external forces," as the French foreign minister later put it.

Soon afterward, Gen. Alexander M. Haig, the NATO commander, began discussions with French officials about renewed U.S. airlift support to bring the French Foreign Legion out of Shaba and to replace it with a force of other African troops.

Brzezinski, just back from his controversial trip to Peking, was reportedly excited at the prospect of this sort of Franco-American cooperation, something not seen since Charles de Gaulle began to distance France from the United States in the 1960s.

But other administration officials argued that the rush to join the French in some new African endeavour was insufficiently thought out. Secretary of State Vance learned on Thursday afternoon last week that the airlift operation arranged primarily by Haig in Europe was literally about to begin without the United States and France having agreed on numerous basic issues. At Vance's insistence, sources said, the airlift was postponed until this weekend. A message was sent to France seeking information on the unresolved issues.

Had the operation gone ahead on Thursday, according to a spokesman for Giscard in Paris, the new African force would have included troops from the landlocked Central African Empire, one of Africa's more improbable countries, ruled with an iron hand by a man who crowned himself emperor last year in a ceremony of ermine and Mercedes Benz limousines that cost millions of dollars. One U.S. official said the administration had been saved a major embarrrasment by delaying the airlift.

Informed sources said Young, at the United Nations, was deeply upset by the course of events, but he held his peace in public. Senior officials in several government agencies expressed dismay at the administration's apparently eargeness to back a hastily assembled force of African soldiers without knowing how this enterprise might end.

The problem, several officials said privately, was that U.S. intelligence saw a real possibility that the Katangese rebels may return to Shaba in a matter of weeks. "They're regrouping," one official said, and several new forays into towns in southern Shaba.

If the Katangese attack again and the new African force has difficulty coping with the attack, the United States could face painful choices.

The administration has advised congressional leaders that it has not agreed to any new commitments to African force apart from the decision to help transport it to Zaire. But congressional leaders have also been told that the United States will consider offering equipment and arms to Africans.

Several officials who express skepticism about the administration's new course - and about the eargeness they attribute to Brzezinski in supporting it - said privately they saw little merit in making a great show of strength in Zaire on behalf of one of Africa's least effective and most corrupt governments.

Officials on the other side of the dispute say Brzezinskiis only being sensible in his conclusion that the strategic arms limitation talks (SALT) and Carter's political stature both may depend on the United States mounting an effective riposte to the Soviet-Cuban presence in Africa.

These sources also claim to see signs that the tougher U.S. rhetoric and action may be working. For example, they claim that Cuban forces are not involved on behalf of the Ethiopian government in its fight against rebels in the province of Eritrea, despite earlier signs that Cubans might enter that struggle.