THE winds of democracy that have swept through Latin America, Asia, Eastern Europe, and the Soviet Union are now sweeping into central Africa. Mobutu Sese Seko, who has ruled Zaire with ruthlessness and rapacity for a quarter century, faces growing unrest that challenges his hold on power.United States policymakers, who have considered Mr. Mobutu a welcome element of regional stability, should now accept the reality that his days are numbered. Mobutu's departure is more likely to contribute to stability and democracy than his retention would. Mobutu follows a long line of discredited dictators, including Haiti's Jean-Claude ("Baby Doc") Duvalier and the Philippines' Ferdinand Marcos, who ruined their countries' economies, looted their treasuries, and corrupted their political systems. Mobutu has also relied on fear and strong-arm tactics to keep extensive national discontent with his repressive rule in check. He now seems to have stretched the patience of his countrymen beyond the endurance point. Corruption on a vast scale is routine in Mobutu's Zaire. Mobutu himself is estimated to have amassed a personal fortune of several billion dollars. He reportedly owns a 16th-century castle in Spanish Valencia, a 32-room palace in Switzerland, an apartment in Paris worth nearly a million dollars, and luxurious estates in Portugal, Spain, Italy, and several other countries. Unfortunately, Mobutu's transgressions go well beyond personal corruption and greed. It is widely acknowledged that his government engages in systematic abuses of human rights. Detention, beatings, and torture are the all-too-frequent fare of Zaire's citizens. The economic effects of a quarter century of misrule have been devastating for what used to be one of Africa's wealthiest countries. Mobutu has even managed to give colonialism a good name by driving his country's standard of living below what it was at the time Zaire obtained its independence in 1960. During the cold war, the US not only supported Mobutu, but even subsidized his discredited regime. Mobutu was necessary, it was maintained, because he provided the stability needed to stem the tide of communism in Africa. Without him, Zaire might well disintegrate into chaos and civil war. But with the cold war over and communism relegated to the ash heap of history, continued US support would place us on the wrong side of some of the most potent forces of the 20th century. Already some of Zaire's elite military units have revolted against Mobutu's rule. Recently the regular Army took to the streets. Looting has been widespread, and French and Belgian troops have been dispatched to the capital of Kinshasa to protect Western nationals. The US should make it clear to Mobutu that the time has come for him to go into exile. Zaire needs a government of credibility and stability, which can't be achieved as long as Mobutu clings to power. He has only one interest - to maintain his grip on the country. If he is allowed to retain a significant share of power in whatever government emerges from the current crisis, he will maneuver and manipulate in an effort to recover those powers he has been forced to surrender. We must be careful not to repeat the mistakes we made in Liberia and Somalia, where a hands-off American policy, combined with a refusal to insist on the departure of dictators Samuel Doe and Mohammed Siad Barre, contributed to the unraveling of the political fabric and ultimately to bloody fratricidal strife. Zaire's recent experiences vindicate the congressionally mandated policy enacted over Bush-administration objections last year that cut off US assistance to Mobutu's military forces and placed new restrictions on the distribution of development aid. As a result of this new policy, people in Zaire today know that the US stands for the promotion of democracy and an end to corruption and repression in their country. The US should demand that Mobutu step down and that power be transferred to a provisional government consisting of credible opposition leaders whose commitment to democracy and human rights is as great as Mobutu's commitment to the accumulation of private wealth and political repression.