A CONFIDENT Boris Yeltsin yesterday won the approval of the Russian parliament to form a commonwealth of independent nations. At the same time, he brushed aside attacks on the accord by an increasingly politically isolated Soviet President Mikhail Gorbachev."I categorically refute allegations that the commonwealth agreement destroyed the Union," Mr. Yeltsin said in his speech. "Not to take decisive measures means to continue to live in the world of illusions. We tried not to destroy but to preserve what was still possible to preserve and to build new relations on a constructive basis." The commonwealth pact was signed last Sunday between the leaders of Russia, the Ukraine, and Byelorussia, effectively ending the Soviet Union as a political entity. Until yesterday, Mr. Gorbachev had opposed the agreement, calling it illegal and demanding approval of the treaty by popular referendum or by the virtually disbanded Soviet legislature. "I will respect the choice of the people if it is constitutional, but if it is based on illegal methods, I will come out against it," he told the daily Nezavisimaya Gazeta in an interview published yesterday. He accused the three leaders of reaching an agreement that contributes to a "process of dissolution." Yeltsin retorted that the accord was "the only step that could end the process of disintegration," the only formula which the Ukraine could agree to after it voted overwhelming for independence on Dec. 1. "What we signed was the union of independent states and not a state where nobody had independence." An overwhelming majority in the Russian parliament backed Yeltsin, with 188 deputies voting to ratify the agreement. Six deputies voted against the pact and seven abstained. The parliaments of Byelorussia and the Ukraine already approved the commonwealth agreement. Parliamentary approval left Gorbachev little room to maneuver. In a meeting with journalists at the Kremlin yesterday, he said he was prepared to support the Slavic commonwealth if it received parliamentary approval, but maintained it would not prevent the collapse of the country, according to the Tass news agency. Gorbachev's attempts since Monday to block the agreement foundered rapidly. His effort to enlist the support of the Soviet armed forces, whose leadership he addressed in a surprise meeting on Tuesday, and of the Muslim-populated republics of the Soviet Union also failed. Gorbachev's 50-minute meeting with the Army included an attack on separatism and a defense of his own draft treaty of political union as the only way to preserve the country. But Yeltsin argued to the military leadership Wednesday morning that the treaty provides for a unified armed forces based on a collective security agreement, including centralized management of nuclear forces. Yeltsin also promised to fund increases in the officers' salaries, starting with a 90 percent hike in January. The armed forces would be smaller, he told the military, but more modern and effective, with continued funding of scientific research, according to the daily Izvestia. "The military completely supported Yeltsin but gave Gorbachev a cold shower," said Col. Vladimir Lopatin, a young military reformer and Yeltsin backer. Yeltsin "has the material base to maintain the Army," added Air Force Col. Gen. Vladimir Shkanakin. "This means he can respond to those concerns and fears that have arisen among servicemen." General Shkanakin said many officers had grown disillusioned with Gorbachev, adding the president's words had not been backed by concrete actions. "He was given the chance to do everything he wanted," Shkanakin said of Gorbachev. "He was given emergency powers to rule the country ... but he didn't use them. I consider this his biggest personal drawback; the absence of willful, authoritative traits." In his attack on the commonwealth treaty, Gorbachev claimed the document was far from clear about how it might work in practice. He raised the question of treatment of "the Asiatic part of the country." But the Asian republics, scheduled to meet in Ashkabad, the capital of Turkmenia today, are reportedly moving to join the commonwealth. Yeltsin told the Russian parliament that Kazakh President Nursultan Nazarbayev was ready to sign in the status of a "co-founder," a move to assuage his damaged feelings over not being invited to the meeting last weekend. In a phone conversation yesterday morning, Yeltsin recounted, Mr. Nazarbayev said that he believed the four Central Asian republics (Turkmenia, Kirghizi a, Tadzhikistan, and Uzbekistan) would also join. The Caucasus republic of Armenia has already indicated its readiness to join, and its neighbor, Azerbaijan, attended the meeting yesterday with the Asian states. Under these circumstances, Gorbachev is looking for a way to compromise. The commonwealth agreement has "many positive moments in it," he said, while insisting that it should be "discussed and synthesized together with the draft union treaty." But Yeltsin already rejected this. "The attempt to stop the process and drown it in discussions has to be ended," he said. At the Russian parliament, most legislators felt it was only a matter of time before Gorbachev's capitulation. The Soviet president's future role in the commonwealth was a hot topic of conversation in the halls outside the parliament chamber. "No doubt Gorbachev should resign," said Shkanakin. "But this is the person who began perestroika, and he maybe should be given some honorary post in some organization - but no more." Gorbachev said yesterday at the Kremlin meeting with Soviet media that he would resign if there were not well-defined central structures of power in the new commonwealth, according to Tass. In the newspaper interview, he rejected the idea of a purely symbolic role in the nation's future power structure, saying; "I don't see myself as the guest of honor at a wedding."