Like every other Soviet Bloc capital, Warsaw was festooned today with red flags and slogans commemorating the 64th anniversary of the Russian Revolution. Fluttering in the autumn breeze, they proclaimed the lofty vision of a communist society free from exploitation, poverty and injustice.

The real world beneath the flags is somewhat different. Sad groups of Poles wait in line for everything from bread to gasoline. Shabby modern apartment blocs and ill-lit streets create an atmosphere of dreariness.

The contrast between ideology and reality was reflected in a letter sent to a satirical Warsaw magazine. The author, Mariusz Michalski, said he was convinced that no action need be taken to extricate Poland from its economic and political crisis -- for the simple reason that, according to Marxist-Leninist theory, the crisis must be illusory.

To support his argument, he quoted from the latest edition of the official Polish encyclopedia, which gave the following definition of "crisis": "a serious breakdown of economic development in capitalism. Crises are inseparably linked with the capitalist economy and do not appear in any other socio-economic system."

But the best demonstration of the hollowness of communism in Poland was provided by the meeting Wednesday of the premier, Gen. Wojciech Jaruzelski; the primate of Poland, Archbishop Jozef Glemp, and the chairman of the independent Solidarity trade union, Lech Walesa. Communist dogma holds that religion is the opium of the people and identifies workers' interests with those of the party.

Here then were the leaders of two theoretically defunct institutions discussing how to save the nation with an Army general representing the Communist Party.

Afterward, Jaruzelski described the encounter as of "momentous importance." Marx and Lenin must have turned in their graves.

Talk of a coalition of national salvation is much in the air. Big obstacles remain, but it seems closer to realization now than at any time since the onset of labor troubles in July 1980. The tragedy is that, by the time such a broad-based government is finally formed, it may be no longer adequate to the task.

The notion of a coalition government was first canvassed privately by some members of the Sejm, the Polish legislature, as early as last November. They argued that the authorities had to find some dramatic gesture to regain their credibility with the nation. Only then could they hope to lead Poland out of the crisis.

The idea proved premature. A token step was taken with the appointment of a progovernment Catholic, Jerzy Ozdowski, as a deputy premier. But the government reshuffle meant little to ordinary Poles, who saw it as another game of musical chairs. Real power remained in the hands of the Party.

When appointed premier in February, Jaruzelski tried to break out of the cycle of truce-conflict-truce by developing new forms of dialogue with the society. But his efforts were sabotaged by hard-liners within the party and government bureaucracy as well as radicals in Solidarity.

At the Communist Party congress in June, Deputy Premier Mieczyslaw Rakowski called for the creation of a broader national consensus. So did some of Solidarity's leading advisers. But once again nothing came of the suggestion, and both sides resumed their attacks on each other.

The continuing labor turmoil has demonstrated that it is impossible to govern Poland without consensus. But, in the meantime, the economy has deteriorated. The ability of any authority, Solidarity and the church included, to control the despair and anger of ordinary people is dwindling fast.

Poland's most charismatic leader, Lech Walesa, even has trouble asserting his authority over his own rank and file. His announcement that he was to meet with Jaruzelski and Glemp triggered a storm of protest from members of Solidarity's National Committee, a kind of union parliament, which was in session in Gdansk.

Suspicious of Walesa's autocratic streak, other union leaders were reluctant to allow him to negotiate by himself. He was accused of violating the union's democratic rules, of planning a sellout, of unbridled arrogance.

Stung by the criticism, Walesa threw what has now become a routine temper tantrum. At one point he threatened "to dissolve the union in two weeks unless we trust each other." Later he pleaded: "Let us not destroy ourselves, it is enough that others try to destroy us."

The delegates finally allowed Walesa to take part in the summit. But the decision was a grudging one and doubts remain that he can deliver his side of any bargain.

The Communist government, too, is divided between the advocates of a final confrontation and men like Jaruzelski who still want to find a peaceful way out.

At different times, one faction or the other is ascendant. But virtually all major decisions during the past 15 months have represented some form of compromise between the two sides.

Jaruzelski's election as party leader on Oct. 18 coincided with a complex maneuver by the regime. At one level it was reflected in a tougher line against alleged "counterrevolutionaries" in Solidarity and the increasing involvement of the Army in public life. At another level, Jaruzelski is trying to assert his own control over the party and build a new, broader national consensus.

This helps explain why Stefan Olszowski, the party's propaganda chief who is generally tagged "a conservative," recently criticized hard-line Communists for refusing to deal with Solidarity. At the same time, the police were instructed to tear down posters stuck up by pro-Soviet extremists.

The result is a confusing and uncertain political situation. Jaruzelski has won some more time to pursue his conciliatory policies, but the outcome is still unclear.

As an elderly intellectual who has experienced all Poland's post-war crises put it, "You foreigners always get it slightly wrong. Our moments of crisis are never quite as bad as they seem from outside. On the other hand, the breakthroughs are never as wonderful either.