THE course of the coup in Moscow recalls two scenarios from recent history: the brutal quashing of the Chinese democracy movement in Tiananmen Square and the successful "people power" movement that ousted Ferdinand Marcos in the Philippines.One important difference between those scenarios, noted Sen. Richard Lugar (R) of Indiana, who was chairman of the Senate Foreign Relations Committee as Marcos fell and acted as special envoy from the Reagan administration to the Marcos regime, is the will of the leadership. Where the Chinese leadership was apparently cohesive and determined to crush the demonstrators, Marcos decided not to use the armed force available to him to retain power. As Senator Lugar spoke with reporters at a Monitor breakfast yesterday, the coup leadership in Moscow appeared to be in retreat. Even if the coup fails and Soviet President Mikhail Gorbachev returns to power, said Mr. Lugar, "My own view is that Gorbachev is a spent force." Mr. Gorbachev has no viable program left for where and how to lead his country, according to Lugar, but he remains "a vessel through which change can flow." Lugar supports President Bush's demand that Gorbachev be returned to office as the constitutional leader of the country, as well as Bush's record of building Soviet policy around Gorbachev. "George Bush used Gorbachev as a vessel for change," Lugar said. While Gorbachev's swings to the right and then back to the left have moved him away from all his constituencies, he has shown "consummate political skill" and was "uniquely able to navigate" between Soviet factions. Lugar is encouraged by the courage of Russian Federation President Boris Yeltsin, which "offer some hope for leadership in the future." Yeltsin will obviously be a much stronger force in Soviet politics, if the coup fails, than he was before. "Yeltsin is sort of tried under fire, and he's going to be a very popular man," said Lugar, adding that Gorbachev would be hard-pressed to face Yeltsin in an election. "My impression is that Yeltsin doesn't have a clear grasp of market economics either," he said, comparing him to Gorbachev. But Yeltsin has a "street-smart" ability to grasp pragmatic and democratic responses. Bush has been blamed by both the left and the right in the US for making the rightwing coup possible. Lugar, a conservative who has always been especially cautious in trusting the Soviets, does not believe it. "There was physically nothing we could have done to prop [Gorbachev] up." The political fallout in the US favors the president, said Lugar, because of "the perception that he is the leader who calls all the other leaders, that he is the center of focus." Americans trust Bush to handle unstable world situations, he adds: "The Soviet situation is clearly not a pat hand, even if the coup group is out soon."