THE armed rebellion of an ethnic minority in the Caucasus mountains of southern Russia is severely testing the authority of Russian President Boris Yeltsin.Mr. Yeltsin's decree of a state of emergency in the Chechen-Ingush autonomous republic on Friday - and the subsequent dispatch of special Interior Ministry troops to attempt to enforce it - have triggered a broad political crisis. The militia of the insurgent movement seeking independence for Chechen-Ingush is openly defying the decree. After two days of intense debate, the Russian parliament refused to back the decree and called instead for political negotiations to be held under parliamentary auspices. And the Democratic Rossiya movement, a key source of political support for Yeltsin, openly split over the weekend, in part over this issue. Some in the democratic movement warn that Yeltsin is following in the dangerous footsteps of Soviet President Mikhail Gorbachev, trying to solve complex ethnic and national disputes by force. They compare it to Mr. Gorbachev's handling of the Baltic demands for independence from the Soviet Union and of the conflict between Armenia and Azerbaijan over control of the territory of Nagorno-Karabakh. "The decree is hasty and thoughtless," Russian deputy Vasily Travnikov told the Russian Information Agency (RIA). "Its realization may lead toward civil war.... We have our experience - the Baltics, Karabakh - and now we are making the same mistake." But others see this as a crucial juncture in which Yeltsin must assert his authority more aggressively than Gorbachev. "This is a test of Yeltsin's decisiveness and his consistency," argues political scientist Adranik Migranyan. "In order not to repeat Gorbachev he has to use force and use it decisively. Either Yeltsin does this or he faces a situation where Russia itself will disintegrate." Under the structure created by the Bolshevik Revolution, the Russian republic is a federation including some 16 autonomous republics representing large national minorities and at least 15 other smaller, ethnically defined regions. The wave of nationalism among the republics has reached into those areas, such as Tatarstan, home of the Tatar minority, and it has influenced various Muslim peoples in the Caucasus, including the Chechen. The challenge to Yeltsin's authority comes at a moment when the Russian government is poised to implement radical and unpopular economic reforms. A plan to free state-controlled prices and pursue rapid privatization will trigger 200 to 300 percent inflation rates, Russian officials admit. Last week Yeltsin announced a reorganization of his government, naming economist Yegor Gaider, principal author of the reform plan, as deputy prime minister in charge of economy. Mr. Gaider, speaking to the conference of the Democratic Rossiya movement over the weekend, said, "We are facing extremely complicated socioeconomic processes and we have already lost control over them." Under these circumstances, Yeltsin's ability to consolidate his political power is crucial, comments Mr. Migranyan, who also attended the Democratic Rossiya meeting. "In order to implement reforms, he must get governability," he says. "But to get governability, he must crush the irredentist movements at the level of republics and even regions." The Chechen-Ingush case will not be an easy one to resolve. The independence movement is led by a former Air Force reserve general, Djakhan Dudayev, who won presidential elections last month organized by his own group. The Russian parliament and government refused to accept the legitimacy of the vote, and an attempt at talks led by Russian Vice-President Alexander Rutskoi, an Army major-general, went nowhere. Russian officials such as parliament chairman Ruslan Khasbulatov, himself a Chechen, dismiss the movement as a "bunch of bandits." General Dudayev's followers are armed with automatic weapons and claim to be able to mobilize a force of 60,000. The Chechen are famous for their guerrilla resistance to Russian rule in the early 19th century. While the democratic movement has gingerly supported Yeltsin's reforms and even his request for greater executive authority, they are openly opposing the emergency decree. "Everything should be done to exclude the use of force," Gen. Dmitry Volkogonov, a military historian and adviser to Yeltsin, told RIA, advocating instead further negotiations involving Dudayev and the local Chechen-Ingush administration. General Volkogonov echoed the feeling of many Russian parliamentarians in blaming Vice President Rutskoi, who drafted the emergency decree, for placing Yeltsin "in an awkward situation." The Russian parliament resolution says the parliament will form a delegation to try to settle the conflict. It calls for moves to control the flow of weapons into the region. And it mandates a parliamentary investigation to determine the individuals responsible for making a decision they say was both politically and militarily unwise. The resolution may give Yeltsin an opportunity to back away from the decree without losing too much face.