As the leader of UNITA, the first of the guerrilla rebellions that have in recent years been turning the tables on Soviet imperialism in the Third World, Jonas Savimbi ought to be having an easy time of it with the Reagan administration.

After all, in enunciating what has come to be known as the Reagan Doctrine, the president has said that the United States "must not break faith with those who are risking their lives on every continent to defy Soviet-supported aggression." If anyone qualifies under that doctrine, it is Savimbi. For more than a decade now, and with no help at all from the United States, he has been at war with the communist government installed in Angola in 1975 and still propped up by Cuban troops and Soviet arms.

Yet whereas the administration, acting in strict accord with the Reagan Doctrine, has begun intensifying its efforts to get military aid to the contras, who are fighting against the communist regime in Nicaragua, it remains opposed to military aid for UNITA, which is doing exactly the same thing in Angola.

A while back there was a certain amount of overt talk about giving covert aid to UNITA. Now the most the administration is willing to ask for is a congressional resolution of moral support. As for the military aid Savimbi has just arrived in Washington to seek, a "senior official" announces that "military solutions to the region's problems are not viable and that a negotiated agreement is the only way to attain peace and stability."

Behind this pronouncement, reeking of the sickly age of Jimmy Carter, is a complicated plan involving the withdrawal of the Cubans from Angola in exchange for the withdrawal of South African forces from Namibia.

"This fine-spun scheme had the usual fate of all exquisite policy," said Edmund Burke about the steps the British government took to avert a rebellion in the American colonies. The count is not yet fully in on the State Departments's strategy for getting the Cubans out of Angola, but it too will almost certainly suffer "the usual fate of all exquisite policy."

Where "exquisite policy" is bound to fail in getting the Cubans out, however, can military pressures succeed?

Savimbi's strategy, as he outlines it in an article in the current issue of Policy Review, is not to defeat the Cubans in some local version of Dien Bien Phu. It is, rather, "to raise the costs of the foreign occupation of Angola until the Cubans and the Soviets can no longer bear the burden." This means denying "the colonial forces the revenues that finance their occupation" and inflicting as many casualties as possible on Castro's troops.

A measure of how effective this classical guerrilla strategy has been is the fact that the Cubans and their Soviet officers have recently begun trying to force Savimbi into abandoning it and to fight a conventional war instead. Thus the question of whether Savimbi can keep up the pressures now turns on whether he will get the antitank and antiaircraft weapons he needs to cope with the new Soviet- Cuban offensive tactics.

In quarters other than the State Department, the main objection to Savimbi is that he is tainted by association with the Republic of South Africa. And, in fact, Savimbi does get aid from the Pretoria government. Pretoria helps him because he is helping to contain Soviet expansionism in Africa; and Savimbi accepts it because he is in no position to refuse assistance from anyone.

But to accuse this man and the movement he leads of supporting apartheid is as absurd as it is defamatory. These are black Africans who first took arms against Portuguese colonial rule and then saw their fight for national liberation betrayed by a minority of Angolan communists who handed their country over to the Cubans and the Soviets. What Savimbi and his people are fighting for now against the new colonial rulers of Angola is the same independence they were fighting for against the Portuguese and that was stolen from them by the communists 11 years ago.

One of the interesting features of Savimbi's career as a revolutionary nationalist is that he got his training in China under Mao Tse-tung in the 1960s. There, he now says, he not only "learned how to fight and win a guerrilla war"; he also learned "how not to run an economy or a nation." His goals, accordingly, are to establish a "democratic and free Angola."

Of course, all parties bidding for American sympathy, including communists, describe their objectives in just such terms. Ho Chi Minh actually paraphrased our Declaration of Independence in drafting his own declaration of independence for Vietnam; Fidel Castro at first called himself a Jeffersonian Democrat; the Sandinistas promised free elections and other democratic institutions in Nicaragua.

Yet the very people who are always so eager to take those promises at face value when they come from communists now scoff at an anticommunist such as Savimbi in spite of the fact that, by contrast with communists everywhere, he has done nothing to forfeit his claim to good faith when he speaks of democracy and freedom.

At a minimum, then, Savimbi deserves the benefit of the doubt even from liberals -- or at least those liberals who still think the United States has an interest in the fight against Soviet imperialism.

But from the Reagan administration, Savimbi deserves more than the benefit of the doubt -- and certainly more than empty expressions of pious support. That the administration opposes giving him military aid violates the president's stated determination not to "break faith with those who are risking their lives to defy Soviet-supported aggression." It is also nothing less than a moral and political disgrace.