WHEN Gennadi Yanayev declared himself acting Soviet president and joined seven other right-wing strongmen in an attempt to take power in the Kremlin, he cited chaos and ethnic strife as principal reasons for the coup. This came as no suprise to students of imperial vocabulary and policy, who know that nationality relations have long been pretexts for decisive displays of central - in this case Soviet - force.That peoples and ethnic groups have feuded for millennia, and continue to do so, is clear. It is beyond question that there are today dozens of places where political discord has degenerated into violent internecine conflict. But when power politics and superpower spins on political reporting push policymakers and newswriters alike into extending the "ethnic conflict" definition to wholly different situations, they run the risk of both misleading the public and legitimatizing totalitarian terror. Armenia is a case in point. On Sept. 21, the USSR's smallest repubic becomes the first in the union to hold a national referendum on independence in compliance with the new law on secession. The new democratic Armenian government's reversal of 70 years of Soviet rule and its commitment to a lawful, peaceful departure from the Soviet Union present Moscow with a constitutional threat surpassing any armed rebellion - though the recent coup may change the character of Moscow's response. In recent months the Kremlin, lacking in Armenia the large national minorities and loyal party apparatus it has employed in the Baltic crackdown, has resorted to a much more devious strategy: strike at democratic Armenia by attacking Armenians living outside the republic's borders. Will that policy continue? An international team of human rights observers led by the deputy speaker of the British House of Lords states that during the past three months the armed forces of the USSR, together with the communist government of Azerbaijan, has forcibly deported more than 10,000 Armenian civilians - 23 villages in total - from their ancestral homes. These traditional Armenian settlements are located near Armenia's borders but in Azerbaijan and in the Nagorno-Karabakh autonomous region. The observers documented violent roundups of civilian populations, murders, rapes, looting, the leveling of entire villages by helicopter gunships and artillery fire, and other egregious human-rights violations. They concluded that Moscow's active, deadly, and one-sided involvement - despite its professed purposes of peacekeeping - is aimed at rewarding Azerbaijan for staying in the communist fold and signing the Union Treaty and at punishing Armenia for choosing the course of democracy and independence. Will this policy continue under the new Yeltsin-Gorbachev government? In remote areas, independent, verifiable information is scarce. The Soviet government has had a keen interest - and time-tested capacity - to explain the blood and destruction caused by its military operations in terms of "ethnic feuding," as if to trivialize the daily suffering and its polictical implications. The Kremlin has found easy customers in American and other Western opinionmakers. During Armenia's three-year movement for democracy, independence, and self-determination for Karabakh's Armenian majority, the United States government and media have become Moscow's ablest spokespersons. By referring to brute force and communist aggression as ethnic hostilities, they have deflected blame from the primary culprit and blurred important distinctions. That, certainly is not the role of our press, and should not be the function of our government. The attempted ouster of Mikhail Gorbachev is chilling testimony to the dangers of this approach. As the Soviet Union prepares to host a September human rights meeting of the Conference on Security and Cooperation in Europe - where the records of member-states will be examined against international covenants to which they are party - it behooves world governments and the professional newspeople who cover them to reasses and correct the ways in which they apply labels to situations. Guilty parties should be held accountable: The brutal Soviet-Azerbaijani expulsion of Armenian villagers is an intolerable response to an entire nation's democratic choice. "Ethnic fighting" or "ancient dispute" is nothing more than excuse and smokescreen for ongoing, modern-day, and state-sponsored violence against innocent human beings. And finding shelter under those terms for the sake of political expediency or an artificial objectivity only serves to ridicule the fairness doctrine and to defeat the terrible truth.