YAROSLAVL, U.S.S.R. -- The Communist Party ideologist and the leader of a radical opposition group in this Volga River city rarely see eye to eye. But there is one point on which they -- and practically everyone else in town -- agree: Living conditions have been getting steadily worse over the past five years, undermining confidence in Soviet President Mikhail Gorbachev and his perestroika reform program.

"When Gorbachev came to power, it was at least possible to buy macaroni. Now everything is rationed," complained Vera Shevchuk, leader of the radical People's Power movement. "People are reaching the limit of what they are prepared to tolerate," agreed Valentin Vinnichenko, a local party official.

"It's difficult to imagine how things could get worse, but they did. Now we are faced with the prospect of chaos if we move to a free-market system," predicted Yuri Petrov, an economic lecturer who heads the conservative United Workers' Front. "This is a dangerous moment. A polarization in society has taken place," said Gen. Alexander Razhivin, the head of the Yaroslavl branch of the KGB security police.

While there is general consensus on the dangers facing the Soviet Union on the eve of a crucial Communist Party congress, there is sharp disagreement on the way out of the crisis.

Shevchuk wants to move to a market economy as rapidly as possible. Vinnichenko advocates caution. Petrov favors the reintroduction of central planning. Razhivin concludes that "all healthy forces" should rally around Gorbachev.

In an attempt to track the changing political and social pulse of the Soviet Union's Russian republic under Gorbachev, The Washington Post has been visiting Yaroslavl, a provincial city of 600,000 people some 150 miles northeast of Moscow. This is the third in an occasional series of articles describing the impact of perestroika on the everyday lives of people in the Soviet Union's Slavic heartland.

Yaroslavl, like Russia itself, has reached a historic crossroads. Reform communism has so far turned out to be even more of an economic failure than the neo-Stalinist model that preceded it. Disillusioned by empty stores and empty promises, ordinary people are losing faith in the slogans of perestroika. The time seems to be approaching when the country will be confronted, not so much with restructuring, but with a much more fundamental choice: either abandoning communism altogether or retreating to an authoritarian, hard-line regime.

On paper, the trend toward greater democracy seems inexorable. In the past six months alone, the Soviet Communist Party has abandoned its claim to a monopoly on political power. A liberal new press freedom law has been adopted by the Soviet legislature, allowing any group of citizens to found its own newspaper. A new generation of radical young politicians has been elected to councils representing the republics and localities, from Lvov to Vladivostok.

At the same time, however, a conservative wind has been gathering strength in the Russian provinces. It was felt last month at the inaugural conference of the Russian Communist Party at which delegates accused Gorbachev of losing Eastern Europe and allowing the dismantling of socialism in the Soviet Union. It is likely to be felt again this week at the 28th congress of the Soviet Communist Party, traditionally the most important event on the country's political calendar.

If the grumbling about perestroika were confined to Communist Party apparatchiks upset over losses of power and privilege, there would be little cause for concern. A few days spent in a place like Yaroslavl suggest, however, that the complaints reflect a broader popular mood. As the politicians in Moscow talk about a transition to a "regulated market" and the "rule of law," normal economic mechanisms are breaking down.

"The deteriorating economic situation is working in favor of the conservatives," said Vladimir Bakayev, a progressive Communist activist at the giant Yaroslavl engine plant who was defeated by a hard-liner in elections for delegates to the party congress. "The conservatives are able to argue that life may have been difficult in the old days, but it's gotten a lot worse now."

The Yaroslavl Popular Front, which burst onto the local scene two years ago with demands for radical reform, has experienced a hemorrhage in its political support in recent months. Some opinion polls give it almost as low a rating as the local Communist Party apparatus: 7 and 6 percent, respectively. The difference is that the apparatchiks can draw on a large and well-oiled political machine, while the opposition is split into competing factions.

"We miscalculated when we assumed that a deterioration in living conditions would result in greater social activity and organized protests," conceded Yuri Antropov, an independent trade union activist at the engine plant. "We thought that misfortune would unite people. In fact, the opposite happened. The disappearance of all kinds of goods from the shops, the introduction of a total rationing system, anxiety over high prices -- all this has led to the political breakup of society. The authorities are taking advantage of this." The Conservative Reaction

Until recently, the conventional wisdom in Moscow was that the 28th Party Congress would seal the fate of the conservative faction in the Communist Party. Through the mechanism of democratic elections, it was argued, Gorbachev would ensure a reformist majority at the congress, the isolation of his political opponents and the renovation of the party.

The pre-congress election campaign in Yaroslavl shows how mistaken the pundits may have been. Of the 26 delegates elected to the congress from the Yaroslavl region, 20 are full-time party activists. Only two of the elected delegates support Democratic Platform, a progressive faction that favors abandoning the disciplinary code known as democratic centralism and transforming the party into a Western-style political party. This would involve dismantling the all-pervasive network of Communist Party cells in the army, the KGB and industry.

At the Yaroslavl engine plant, which was the site of one of the first significant workers' protests under Gorbachev in 1987, hundreds of Communists have already left the party. Many joined the party not for idealistic reasons, but simply as a way of getting ahead. Only half the remainder bothered to take part in the election campaign. A majority appear to have voted for the official candidate, the chief engineer of the factory, out of a mixture of concern about the future and obedience to management.

"The prospect of unemployment and higher prices frightens people. We have had no experience of a market economy. For 70 years, they've grown accustomed to a system of minimal social guarantees. They fear that serious changes in the economy could lead to even greater social disruption," said Bakayev, the losing candidate who collected about 40 percent of the vote.

For all the talk about economic reform in Moscow, there is little evidence of any real changes here in Yaroslavl. The engine plant, the largest factory in the region, is still obliged to hand over 100 percent of its production to the state. Ration cards for vodka, butter, meat, eggs and macaroni were introduced last month, and the newly elected city council is now debating a comprehensive rationing system for everything from linoleum to winter coats. The system is meant to last well into the 21st century.

Even cautious moves by the government toward a free market have provoked a sharp counter-reaction. When Prime Minister Nikolai Ryzhkov mentioned the possibility of price increases on staple products at the end of June, there was a wave of panic buying across the country. The radical-controlled Moscow city council restricted sales of food products and consumer items to nonresidents -- whereupon the Yaroslavl authorities countered by cutting vodka sales to the capital. Consideration was even given to stopping deliveries of new engines to a Moscow truck plant.

"The people of Yaroslavl were offended by the decision of the Moscow city authorities. We were obliged to introduce rationing here," said Igor Tolstoukhov, the regional Communist Party chief.

The management of the engine factory has given its tacit backing to the United Workers' Front, a conservative pressure group fiercely opposed to economic reform. At present, the front seems to enjoy little real support from the largely apathetic work force. But its spokesmen are maneuvering themselves into a position to be able to say, "We told you so," if the government's economic reform program leads to mass layoffs and price increases.

The conservative majority at last month's Russian Communist Party conference was made up of delegates from towns and cities like Yaroslavl. Their votes helped elect the hard-line Ivan Polozkov as the leader of the new Russian party. As the regional Communist Party chief in Krasnodar in southern Russia, Polozkov conducted a furious campaign against the cooperative movement, a form of semi-private enterprise officially encouraged by Gorbachev.

At a meeting last week with Communist Party workers, Yaroslavl delegates complained of picketing and other forms of harassment by Muscovites during the conference. "They waved signs reading, 'Down with the reds' in our faces," a delegate recalled with a shudder. Other speakers demanded measures to protect the reputation of Soviet state founder Vladimir Lenin, including the renovation of his statue in the city's main square. Disillusionment Sets In

It is easy to dismiss the views of the offended party bureaucrats as wildly out of touch with public opinion and, therefore, irrelevant to the future of the Soviet Union. But the party remains the ruling party. The Communist apparatus may have lost power in the big cities like Moscow, but it is still entrenched in smaller places like Yaroslavl. And as Shevchuk points out, "There is only one Moscow, but there are many Yaroslavls."

The Popular Front's candidate, Igor Shamshev, upset the party establishment in March 1989 to represent Yaroslavl in the Soviet legislature. But opposition candidates fared badly in local elections this year. Only 17 percent of district council members and 43 percent of the city council members are allied with the opposition.

What seems to have happened is that people who voted for Shamshev last year stayed away from the polls this time around out of disillusionment with the lack of real change. The turnout plummeted from around 80 percent to 50 percent in many districts, barely enough to ensure a valid election. Establishment candidates were able to exploit their superior organizing ability and power of patronage to get out the vote.

"You must remember that perestroika was a revolution from above," said Pavel Nikitin, a local journalist. "The Soviet Union is not like Poland. Solidarity was a revolution from below which was able to take power into its own hands. People here don't believe in anything anymore. They have not understood the depth of the crisis we are facing."

To become irreversible, any revolution needs to acquire a critical mass, a point at which the number of active supporters outweighs the number of committed opponents. That point may have been reached in Moscow, Leningrad and a few other cities, but it has not been reached all over the country. Provincial cities like Yaroslavl have now become potential cradles of counterrevolution.

Despite the sharp criticisms of Gorbachev at last month's Russian party conference, the Soviet president is probably not in immediate political danger. In an interview, Tolstoukhov, the regional party chief, said he would support Gorbachev's reelection as party leader at the 28th party congress as the only figure capable of keeping the party's factions together. Other regional party bosses probably feel the same way. Even the conservatives have no interest in seeing the party fall apart completely.

The real threat to Gorbachev is not political opposition within the Communist Party, but the deteriorating economic situation in the country. The crisis is almost bound to get worse before it gets better. Attempts to introduce meaningful economic reform will run into opposition not only from Communist Party hard-liners but also from the work force.

"Spontaneous workers' uprisings are quite possible," predicted Antropov, the secretary of a discussion club at the engine plant. "If the workers feel that their already low living standards are threatened, then they will revolt. They will march to the town square and demand higher salaries and more consumer goods. Anything could spark it off."

By opting for gradual economic reform, Gorbachev has sought to lessen the risk of uncontrollable upheavals. But he has ended up satisfying no one. The disruption of the old economic mechanisms has caused production to decline and goods to disappear from stores. The prospect of a social explosion has been delayed rather than averted. In the meantime, Soviet citizens have no guarantee that they will eventually reap the benefit of a market economy.

"Gorbachev will have to choose which side he is on. To sit on both stools at once is becoming impossible," said Bakayev, who is now wondering whether he should quit the party if the changes demanded by the Democratic Platform are not adopted at this week's congress.

One conceivable way out is for the Soviet leader to throw in his lot with the radicals led by his old political adversary, Boris Yeltsin, who was elected president of the giant Russian republic in May. The former gadfly of the Politburo has one significant card to offer Gorbachev: popularity. He is probably the only Soviet politician who could rally significant public support for a new economic reform program.

Another possibility is for Gorbachev to set aside his democratic inclinations and opt for an authoritarian solution to the crisis. Emergency powers at the president's disposal allow him to ban strikes, suspend democratically elected soviets and use the army to ensure normal economic activity.

A third possibility, which seems unlikely now but cannot be ruled out over the longer term, is a military coup supported by disaffected Communist Party apparatchiks and Russian nationalists. A Soviet army general, Albert Makashov, won wild applause from the Russian party conference when he pledged that the armed forces would "not surrender" to the ideological enemy and would not permit the dismantling of Communist Party controls.

All the conceivable ways out of the crisis are fraught with danger. Yeltsin's popularity rests partly on his insistence that economic reform need not mean higher prices; his supporters may turn against him once they discover that this may not be the case. An authoritarian solution might stabilize the economy over the short term, but it would not resolve any of the Soviet Union's underlying problems.

In the meantime, Gorbachev is still hesitating about which way to jump. Some of his closest supporters, including government ministers, are publicly criticizing him for indecision. In Yaroslavl, his wavering has prompted comparisons with other fateful episodes in Russian history, including the failed Decembrist uprising in 1825 when a group of aristocratic officers refused to take the ultimate step and overthrow Czar Nicholas I.

"Gorbachev is a prisoner of his own class, the Communist bureaucracy," said Jana Nikitin, a freelance journalist. "When I think of him, I think of the Decembrist officers standing in Senate Square in Petrograd, not daring to move. If they had seized the initiative, they might have won. But they waited to be carried away by history. What we are witnessing now could be Gorbachev's Senate Square."