Of the foreign trouble spots of the early 1960s, "the Congo is the only place where U.S. policy could be described as a lasting success in cold war terms," Madeleine G. Kalb writes in her book, "The Congo Cables." And that success, she adds, "has rested largely on the efforts of one right- wing general." His name was Joseph Mobutu, and in the East-West power struggling over the newly independent Congo, he was the chosen instrument of the United States (and the CIA).

In the natural course of "Africanization," he now calls himself Mobutu Sese Seko. The Congo is called Zaire. Yesterday, as its president by a bloodless coup in 1965, he paid his second call on Ronald Reagan at the White House. And it is safe to say there are few world leaders that Ronald Reagan would rather be seen with at a time when his administration's foreign policy is checkmated in the Middle East, dangerously adrift in Central America and not going anywhere, so'd you'd notice, elsewhere in Africa or the Third World.

Zaire's tumultuous history and the American involvement in it are nowhere better recorded than in Kalb's book: the mutiny of the security forces as the Belgian colonialists departed; the United Nations peace efforts; the mysterious murder of Patrice Lumumba; the near-secessions of what we used to call "the breakaway Katanga province" (now called Shaba) with its vast mineral riches; the bloodshed, the violence and the rough repression.

Not a pretty story, in many ways. But a resounding defeat for the Soviets (remember Nikita Khrushchev's frustrations as he pounded his U.N. desk with his shoe?) and a ringing vindication of much that Ronald Reagan holds dear--if only a queasy Congress and a gun-shy public would free him up to practice things like timely military aid as needed and vigorous covert activity falling just short of U.S. combat involvement; a hard-eyed priority for the big picture of national security over the nitty-gritty of human rights and official corruption. That's the way the Congo game was played.

And that is why the Mobutu government is almost a monument to U.S. Ambassador Jeane Kirkpatrick's (and the administration's) doctrine on dictatorships. Mobutu is "authoritarian" as distinct from "totalitarian" (communist). He is staunchly anti-Soviet. His country is strategic by definition, for its vital minerals (cobalt, copper and diamonds) and its geography, smack in the middle of a sea of African instability.

As we are seeing at this very moment, Mobutu is helpful. Some 2,000 of his troops are available in Chad for use against the invading forces of the noxious Libyan bomb-thrower, Muammar Qaddafi. The U.S. commitment to that struggle is measured by an emergency $10 million airlift of military supplies to Chad and the urgent delivery of hand-held anti-aircraft weapons to resist attacks by Libyan jets.

Zaire has been a faithful friend as a member of the U.N. Security Council on the U.S. side of the Nicaraguan question. New York Mayor Ed Koch is not merely being polite by holding a reception for Mobutu; not long ago Zaire became the first African state to restore relations with Israel after the big African rupture with Israel at the time of the 1973 Mideast war.

Mobutu meets another Kirkpatrick test of authoritarians: of late he has been moderately responsive to U.S. urging that he clean up his act on two counts. He has been releasing political detainees at home and allowing some important exiles in opposition to return to Zaire. He has also accepted a stiff regimen laid on him by the International Monetary Fund in the interest of sounder economic management.

None of this is likely to appease Mobutu's American critics, mostly Democrats on the left. His high standing at the White House thus defines one side of a fundamental argument over American foreign policy in much the same way that U.S. support for the shah of Iran--and his downfall--joined the issue. For what Mobutu has not done, and probably cannot do, is to provide any succession process. "He is it" in Zaire, says one U.S. diplomat--which is fine, in some eyes, as far as it goes. But being "it" may also be an invitation to disastrous instability once this "linchpin" of central Africa, as an American expert describes Mobutu, is gone.

In that sense, Mobutu Sese Seko is both a success symbol and an irrelevant relic of another time and a different world. Not just the U.S.-Soviet balance of power has changed. In the early '60s, the American public had yet to suffer through the shock of Vietnam, the relevations of CIA excesses, the multiple demonstrations over two decades of limits on U.S. power to control events.

For all these reasons, "the efforts of one right-wing general" can no longer be counted on in the 1980s to safeguard the success of U.S. policies which actually did not even work all that perfectly 20 years ago.