AT 85, YUGOSLAVIA'S President-for-life Tito, currently in Washington, basks in the glow of the political miracle he has performed in his own country and of the international company he has kept for 40 years. He is, you might say, the Gordie Howe of international politics, someone admired - like the nearly 50-year-old pro hockey player - for astounding longevity but also for playing a world-class game.

President Tito has been around so long people tend to forget, or not to have had occasion to have learned, just what he did. Having embraced communism, he led one of the pricipal Yugoslav forces that ousted the Nazis in World War II and then wiped out his rivals for power and created a united Yugoslavia - in the very region, the Balkans, whose name is a synonym for violent ethnic fragmentation. When Stalin tried to destroy him, he summoned up Yugoslav nationalism anew and, with a lot of Western help, held on.

His policies since have flowed from his perceived need to keep Yugoslavia from buckling or splintering under Soviet pressure. Partial liberalization - advanced by communist standards - has made possible an association with the West essential for a country needing an economic alternative and strategic counterweight to Moscow. "Nonalignment" - detachment from great-power blocs - had given Yugoslavia access to a protectively broad number and range of countries in both an East-West and "North-South" framework. If President Tito has not ensured that Yugoslavia will be spared Soviet subversion or ethnic explosion when he's gone, it's not for lack of trying.

For 30 years the United States has figured that President Tito's defection from Moscow constituted so valuable a strategic boon as to preclude any serious American quarrels with Belgrade on other grounds. Who wants to see the Russians in the Mediterranean? Only occasionally has any administration complained that Mr. Tito was playing an anti-American game in this or that area of policy, secure in the knowledge that for strategic reasons Washington would do no more than grumble.

The Carter administration has taken a mellow approach to the old man. It has flattered him by intensive consultation and avoided taking umbrage at his prickliness. The administration is applying a kind of political body English in the hope that the relative calm and stability he has given his country is not entirely or even greatly a function of his personal rule.