It has been said that Jimmy Carter's naive preoccupation with "human rights" created problems for the United States in its international relations.

What has been less remarked is that Ronald Reagan's single-minded anti-communism may end up creating far worse problems.

In particular is this true in the case of southern Africa. For while communism may be the bete noire for the Reagan administration, South Africa is, for many Americans, including nearly all black Americans, the unchallenged bete blanche.

But South Africa is also steadfastly anti-communist. It is the intersection of those two facts that bids to make trouble in the coming months.

According to Randall Robinson, head of the pro-Africa lobby Trans-Africa, the trouble may already have begun in terms of American relations with black Africa.

He sees, in remarks made by Secretary of State Haig, a repudiation of the Africa policy that guided the Carter administration: a policy whose chief tenet was that our dealings in Africa should be premised on U.S. and African interests, not on the U.S.-Soviet conflict. p

"The Haig theory," says Robinson, "is that the Saudis and other Third-World American allies would perceive American weakness if we were not to respond to every Soviet activity. So the real thrust of the Reagan administration will be to ignore Africa when it can, but to see Africa only through the lens of the Soviet Union -- which, in all likelihood will put America into a de facto alliance with South Africa.

For example, Reagan said during the presidential campaign that he favored military assistance to Jonas Savimbi leader of the UNITA forces that still refuse to accept the legitimacy of the government that drove the Portuguese out of Angola. Savimbi, who is anti-communist, has been aided in his guerrilla activity by South Africa.

Even during the Carter presidency, Robinson was dismayed that the United States was the only Western power that refused to recognize the government of Angola. (The other Western nations, and all the African powers, have long since recognized the government.)

"Now, under Reagan, we find not only non-recognition but support for [Savimbi's] attempts to overthrow that government," Robinson said in a recent interview.

The sticking point for both the Carter and Reagan administrations is the presence in Angola of Cuban -- communist-troops.

Robinson believes that the Cubans will leave when South Africa no longer poses a threat to Angola's stability. But he questions the basic premise: "We recognize East Germany, and there are Soviet troops there," he said. "We even recognize the Soviet Union, and there are certainly Soviet troops there. But we don't recognize Angola, despite the fact that Angola has all of its trade relations with the West and has, in fact, been reaching out to the West for a better and warmer relationship.

"And, now, the climate has worsened -- frighteningly -- because the United States is talking about just seeing the thing only in terms of combating Soviet penetration and forgetting about African objectives."

The irony is that such a policy won't work, even on its own terms. African countries that need help, economic or military, are going to get that help where they can find it. It doesn't come from us, because it doesn't fit with our emphasis on anti-communism, the result is likely to be that they will turn to the communists: the Cubans, the Soviets and the Chinese. Which, as Robinson reads the signs, means that the people who had sought our friendship become, bydefinition, our enemies.

It doesn't make sense, even in terms of thwarting Soviet expansion. As George McGovern once put it, if the Soviets come out against cancer, does that mean we have to come out in favor of it?