CAN YOU recall the not so distant day when the history of the world, for the rest of the century anyway, seemed poised on the question of whether Mikhail Gorbachev would crush cheeky Lithuania's bid for independence? "Do not wait for tanks from Gorbachev," muttered the man himself. He was as good as his word. That particular moment of danger passed. Lithuania and the world were spared whatever dire consequences an invasion would have brought. The issue of modernizing republic-federal relations in the Soviet Union was transferred from apocalypse to drudgery, becoming just another grind of reform. This is how you could read the story "Armenia Declares Its Independence" in this newspaper the other day on Page A18.

Of the 15 Soviet republics, the bulk have made political assertions at one point or another along the spectrum ranging from "independence" to "sovereignty" and the rest are studying the possibilities. The Gorbachev government has abandoned the coercion that enforced Soviet socialism's 70-year pretense to create "unity and friendship" among the Soviet peoples. The Kremlin has settled down to negotiating terms of independence with the most insistent republics, the Baltic three, and is preparing a new law to recast the republics' overall relations with the central government. As Americans know well, keeping federal-state relations responsive to changing needs is a large part of what democratic government is about. The Soviet Union is exploring federalism with a weak tradition of voluntary association to draw on. Ethnic differences aggravate the difficulties. Meanwhile, the political system is in chaos and the economy in disaster.

An independent Armenia? Certainly the Armenians have a cultural and historical identity. Briefly, after the breakup of the 19th century European empires in World War I, they had a state -- until the Red Army came in. Socialism has brought them, in addition to the mixed blessings of Soviet control, vicious tensions with neighboring Azerbaijan. To reject the one is to risk exacerbating the other.

The preferred American way in Soviet nationality disputes is to emphasize process over outcome. Mindful of considerations of stability as well as ethnicity, the United States endorses peaceful negotiations as a method of change. There's nothing noble to this approach; it tends to make the United States neutral as between the Kremlin's and the republics' competing claims. But it offers modest encouragement to the compromises essential to a satisfactory and enduring result.