A SURGE of Soviet-American diplomatic cooperation has brought Angola within reach of a cease-fire and a political settlement. The Soviet and American foreign secretaries each received the Angolan figure supported by the other and, with Portugal's assistance, produced a formula that promises to free Angola from 15 years of unbelievably debilitating civil war. From the "cross-talks" emerged a consensus for a cease-fire, including the termination of military aid by both Washington and Moscow, and for a political process meant to culminate in internationally monitored elections. With luck, all this should be wrapped up in talks in Lisbon next month.

It is instructive to ask what brought this progress. First comes the attainment of a military stalemate, which was made possible by American readiness to keep Jonas Savimbi's UNITA in the field against government forces receiving 10 or more times the aid from Moscow. Then comes the MPLA government's agreement to open the political system and make a place for UNITA. Just last month the ruling MPLA, until then a self-styled Marxist party, endorsed the concept of a multiparty democracy and free-enterprise economy and took up proposals to separate the MPLA from the state apparatus and the army. With a peaceful way into the system thus available to him, UNITA's Savimbi dropped his demand for direct recognition by the MPLA. This creates an interesting situation: the changes newly professed by the MPLA make it at least in theory a more democratic party than UNITA, which speaks of pluralism but which Mr. Savimbi runs on Leninist lines.

Angola's future as a democracy may be conditional. Just to be delivered to peace, however, is a boon, and meanwhile its travail will have made its own global contribution. The Soviet Union chose Angola in 1975, when the Portuguese colonies disintegrated, as an outpost for a geopolitical assault on southern Africa. The West's, and especially Washington's, response not only blunted this regional strategy but also played a part in prompting the Kremlin and the Soviet people to undertake a fundamental policy review. All the results in Moscow are not yet in. But the result in southern Africa has been to let the countries there turn to their immense domestic problems in a context of regional calm and widening association with the outside world. This is no small achievement.