MOSCOW — GARY KASPAROV may be world chess champion, but he's still a novice when it comes to politics.At a recent Moscow rally in support of reform-minded politicians, Mr. Kasparov approached the podium with the confidence of a grandmaster. But when he opened his mouth to address the crowd of about 50,000, nothing came out. He stood at a loss for words for nearly 20 seconds, laughing at his own stage fright, before loosening up and urging the crowd to participate in politics. ve spoken before in front of crowds, but never to so many people," he told the hushed crowd. "I just had to pause for a while to get accustomed." Despite his relative inexperience, Kasparov has emerged as one of the leaders of the Democratic Russia movement, which backs Russian President Boris Yeltsin. Some consider Kasparov second only to Mr. Yeltsin in influence. Kasparov has challenged the Soviet establishment since his first duel for the world chess title in 1985 with arch-rival Anatoly Karpov, a staunch backer of Soviet conservatism. The match was halted due to "player exhaustion." Kasparov later won the title from Mr. Karpov and defended it successfully late last year. He explains that the transition to politics was a natural one. "If I want to feel like a proper citizen of the country - a man who is contributing something to the country's future - I shouldn't miss this opportunity to present myself, my views, and the views of millions of people who cannot be heard," says Kasparov, wearing blue jeans in his modest central Moscow office. Avoiding politics would be unforgivable given his position, he adds. "My absence from the political stage would be a great disaster for the democrats," Kasparov says. "If people see Kasparov ... and he is silent and doesn't want to interfere in politics they'll say 'What can we do?' and will stay away." Kasparov's desire for a market economy in the Soviet Union is tied to his budding business interests. Along with ventures in the Soviet Union, Kasparov says he has invested his earnings as chess champion in projects overseas. Kasparov has worked behind the scenes for years doing what he could to boost the influence of reformers. He helped bankroll Yeltsin's presidential campaign. He declines to disclose the specific amount of his contribution, saying he fears such information could be manipulated by hard-liners. Also active in politics is Kasparov's rival, Mr. Karpov, who is a member of the Soviet parliament. Karpov also chairs the Chernobyl Help group, which gives aid to those affected by the 1986 nuclear power plant disaster. Yeltsin's goal of introducing democracy in the Soviet Union won't be easy to reach, even after his election as president of the Russian republic on June 12, Kasparov says. "After almost 75 years of dictatorship, of course [the Russian people] have little conception of democracy," he says. "The basic idea of the democratic movement is anti-communism," he continues. "Maybe that's good, but sometimes that could be very bad because they'll blame communists for everything bad in the country.... If they're convinced the communists are responsible for everything, they can start to kill communists as they killed anti-communists 75 years ago." The logical next step for the democrats is to form an alliance with the emerging new class of Soviet entrepreneurs, Kasparov says. His model for this sort of alliance is Britain's Conservative Party hard-line fiscally with a social conscience," he says. "This unity could be useful for both sides," he says. "The democratic movement will get money and financial support. And the enterprises will get the political force that will defend their interest." Kasparov hopes to be a point man for this in his role as a businessman. While he waits for the proposed alliance to take shape, Kasparov is busy working to form the Liberal-Conservative Union, an outgrowth of the Democratic Party of Russia (DPR). He split with the DPR in April, complaining of too much anti-communist rhetoric. A program for the Liberal-Conservative Union should be prepared in August, the Russian Information Agency reports. Internal squabbling in the DPR may also have prompted Kasparov's departure. Over the weekend, for instance, members of the Social Democratic Party voted not to join a coalition of reformers, saying they wanted to preserve their own power structures. All the political and business activity is taking its toll on the champion's chess skills. He has played poorly in his two most recent tournaments. "I lost ... mostly because I couldn't concentrate on chess. I had too many other things on my mind," he says. Nevertheless, chess remains the most important thing in his life, Kasparov says, adding he plans to take a working vacation in California this summer to regain his championship form.