NEWS ANALYSIS : Yeltsin Mystery: True Democrat or Tyrant? : Kremlin: The enigmatic Russian, facing enormous challenges, draws open criticism from former backers.

Boris N. Yeltsin has overthrown one of the most powerful states in modern history, forcing the breakup of the Soviet Union and the resignation of Soviet President Mikhail S. Gorbachev. But Yeltsin’s next moves as Russian leader are question marks.

Just how will he pull Russia from the ruins of Soviet socialism?

His actual policies remain formulated in vague, sometimes contradictory terms. And further questions arise from the sharpening conflicts among his supporters and advisers, from his staff’s penchant for operating in secret and from a character that he himself describes as “impetuous” in some circumstances and “harsh and rigid” at other times.

“The phenomenon of Yeltsin must still be revealed before we can characterize him fully as a politician,” Gorbachev said this week before he resigned. “So far, we have studied Yeltsin largely as an opposition figure, and here he has shown he can do a great deal, and he has done a great deal.

“We hope that he is fully aware of the great responsibility now on his shoulders,” Gorbachev added. “The euphoria of election campaigns is over, the rights have been achieved, power has been achieved. With this has come a great responsibility, and he still needs to understand that.”

Yeltsin came to power with the broadest, noblest of goals: Full democracy for a people who have never been free; economic prosperity through development of a market economy and an international role for Russia that promotes mutual security, disarmament and peace.

As pragmatic and tough a politician as ever emerged from the Soviet system, Yeltsin, 60, a construction engineer and former Communist Party boss from Sverdlovsk, courageously proved his commitment to democracy last August when he rallied the popular opposition to the conservative coup.

He demonstrated it again in recent weeks when, convinced of the impossibility of fundamental reform within even a reconstituted Soviet Union, he forced its dissolution to bring socialism to an end.

And his record over the past three years battling Communist Party conservatives and often Gorbachev in making his political comeback shows a radical but consistent approach to the country’s problems--an increasing conviction that only after ending socialism would the crisis ease--and a willingness to act boldly where Gorbachev hesitated.

But open criticism, not just questions, now comes from many of Yeltsin’s former supporters.

“There is no democracy in Russia, there is no power, only chaos and anarchy,” Maj. Gen. Alexander V. Rutskoi, Yeltsin’s own choice for Russian vice president, said this month, complaining to the press that the president has become a captive of his staff. “Everything is falling into an abyss--the economy, finances and, most important, the trust of the people.”

Tatyana Koryagina, a radical, free-market economist Yeltsin once considered for his Cabinet, said this week that Yeltsin’s “chief characteristic as a politician is his total unpredictability. Wild expectations are generated, but the deeds that follow tend to dishearten the people. This produces a kind of psychological stupor that can, in an instant, turn into a social volcano as people come to. The new sum of his policies leads us inexorably to a non-parliamentary regime.”

And Yeltsin himself, sometimes as candid in power as he was in opposition, has acknowledged serious errors as president, including the dispatch of troops, later recalled, to the troubled Chechen-Ingushetia region when he was misled by his personal representative who was feuding with the popularly elected leadership there.

“A sincere man,” Gorbachev said of Yeltsin during an interview last weekend with CBS Television. “I wish he could always be consistent, without vacillating. I wish he wouldn’t give in to pressure, and I would wish the same thing for myself. . . . And I wish he were more democratic--it wouldn’t hurt him.”

Whether Yeltsin is a true democrat--or a potential dictator--matters far more today than it did just months ago. The question had less import before, because Gorbachev appeared likely to remain as president of a “confederative state” pulled together from the remnants of the Soviet Union, and Yeltsin would be president of Russia, its largest member. Yeltsin’s role was to be the “bulldozer,” breaking down opposition to Gorbachev’s reforms and marshaling popular support for them. “If Gorbachev did not have Yeltsin, he would have to invent him,” the burly Siberian was fond of saying of his often testy relations with the Soviet president.

But Yeltsin broke with Gorbachev late last month in a final, telling dispute. It brought about the collapse of the Soviet Union and the ascendancy of Russia in its place.

Yeltsin believed that he, the other republic presidents and Gorbachev had agreed on a new union treaty that left a minimal central government in a major decentralization of power; when he saw that the draft retained more than that, he refused to sign, arguing that it amounted to preserving the Soviet system.

“Boris Yeltsin is not a man who blinks,” a Russian official commented later. “That’s what Gorbachev expected--for him to blink, to say, ‘Yes, we have come this far, so let’s sign and fix it later.’ ”

But Gorbachev aides accused Yeltsin of negotiating in bad faith, of waiting for a decisive moment, then overturning the agreement on a pretext to maximize power in his own hands.

“In one blow, Yeltsin ended Soviet power and socialism, restructured the state and ousted Gorbachev,” one of the former president’s political advisers said. “It was a brilliantly plotted strategy, and it was well played, but it was done with total disregard for the country. Yeltsin’s partners and his adversaries should learn from this.”

Of himself, Yeltsin said the confrontation had brought out the “steel” in him, a result of the 30 years he worked in Sverdlovsk, an industrial center in the Ural Mountains that is now known again as Ekaterinburg. “The people there are tough and exacting,” he commented. “They don’t like blather, empty talk. I was raised in that atmosphere. That is certainly what makes me tick.”

But Yeltsin is seen by his increasingly numerous critics, who range across the political spectrum from ousted Communist bureaucrats to Gorbachev aides to leftist radicals, as gathering for Russia, and for himself, the very powers--and more--that he denied Gorbachev and a continued central government. Under Yeltsin, his critics warn, Russia is plunging into a demokratura, a term combining demokratiya with diktatura.

“I have ventured to take unpopular measures,” Yeltsin commented recently. “Therefore, I don’t think I can expect ardent affection from the Russians. On the contrary, there is growing criticism of me. So, if portraits of me have sprung up in some places (such as government offices), then no doubt they will soon start tearing them down. I am even expecting that.”

But Yeltsin’s supporters, still by far the Russian majority, gave him a mandate for radical change when they elected him in June over five rivals; Yeltsin said he will forge ahead on economic reforms on Jan. 2, ending state subsidies and raising prices up to fivefold to cover production costs.

“Everything depends on economic reforms, which have been hindered in all possible manner until now,” Yeltsin told the Russian lawmakers this week. “The situation will deteriorate for a period of six months after the liberalization of prices.”

The great fear, as he conceded, is public protests as food prices triple and unemployment then soars as enterprises try to cut their costs: “We shall try to explain to our people that these will be temporary sacrifices, that the situation will stabilize in a year and we will yet see a brighter future. People should be given something to believe in, but six years of perestroika did not raise their living standards and the situation even deteriorated. We have to do better if there is to be hope.”

But Koryagina, one of the country’s boldest free-market economists, sees crucial flaws in Yeltsin’s program--notably, the failure to privatize the economy first and break the monopolies that state enterprises now have--adding to the social pressures and defeating the reform.

“Yeltsin does not seem to realize how dangerous our economic situation has become,” she said. “Worn-out pipelines, the lack of spare parts for nuclear power stations, broken-down sewage systems--everything threatens disaster, and any can cause a volcanic eruption.”

The program for a fast-paced push to a market economy that Yeltsin outlined two months ago remains “operative,” according to Yegor T. Gaidar, the Russian deputy prime minister for economic policy, and scores of implementing decrees and orders have been prepared.

Yet such is the secrecy now among Yeltsin’s top advisers that no one outside that circle--not members of the Russian Parliament, not his allies in the Moscow and St. Petersburg city governments, not the commentators in the pro-Yeltsin press--knows what precisely the program is and how it fits together.

“Let’s wait three months,” Alexander N. Yakovlev, for almost seven years Gorbachev’s closest adviser and the intellectual father of perestroika , said in an interview when invited to criticize Yeltsin’s program. “I was never afraid to criticize anybody. But times are so tough now that I think if a man takes up this burden let him try. Yeltsin should be given this chance.”

Criticism, in fact, is multiplying.

Newspapers on both the radical left and the right complain that new Russian government regulations reducing or eliminating subsidies, increasing delivery costs and raising prices for paper and printing aim to silence those with views different from Yeltsin’s.

Moscow Mayor Gavriil Popov and St. Petersburg Mayor Anatoly Sobchak, both one-time Yeltsin allies, are now sharply critical of him--over economic reforms, over the breakup of the Soviet Union, over the closed character of Russian policy-making in recent months.

But Yeltsin has an electoral mandate unparalleled in Russian, or Soviet, history: He is the nation’s first popularly elected leader. “Boris Yeltsin can say, ‘I am the people’s choice,’ and that is a first that carries a lot of weight,” Sergei Plekhanov, a political observer here, remarked. “Yeltsin can then say, ‘This is what they want me to do,’ and who can argue with him? In fact, people voted for Yeltsin precisely because they wanted change.”

And Yeltsin’s mandate was validated in August when he led the opposition to the rightist putsch--and saved all the gains of the Gorbachev years.

It was renewed again in the minds of most people when Yeltsin brought to an end, as painful and poignant as it was for many, the Soviet experiment in socialism.

Now, Yeltsin is trying to rally this popular support he has commanded and is preaching confidence in the future.

“It is difficult for us all now, and it is not going to get any easier in the next few months,” Yeltsin told the trade union newspaper Trud this month. “The main thing is confidence. And faith. Don’t give up, don’t sink into pessimism, don’t lose hope. That is the important thing now. New times are on the way.”