ne year after the birth of Poland's independent trade union federation Solidarity, there is a sense here that the second--and perhaps decisive--act in the drama is beginning. For, after allowing power in Poland to drift for the past 12 months, both the Communist Party and Solidarity are attempting to consolidate authority.

Here lies the significance of the two congresses Poland has just witnessed, the party congress in July and the Solidarity congress last week. Each was preceded by an election campaign. A widely held view was that this would result in a victory for the political center--and that the reformers in the party and the moderates in Solidarity would be able to bargain with each other.

Such an "optimistic" scenario still remains possible. But, for the moment, the opposite seems to be happening: there has been a polarization of opinion on the two sides.

Under heavy pressure from Moscow, the party has stopped making concessions to Solidarity for the sake of social peace. It has moved to reassert its control over the mass media and, despite the self-evident failure of the economy, is still dragging its heels on reform. Within the party, power seems to be shifting to a group of hard-liners around the propaganda chief, Stefan Olszowski.

On the other side, meanwhile, Solidarity leader Lech Walesa has managed to fend off a challenge to his position from the union's radical wing. But the movement is split, and the rank and file is chafing increasingly against self-imposed constraints designed to avoid the danger of a Soviet invasion. The first stage of the congress ended with a call for free elections and a message of support for free trade unionists elsewhere in Eastern Europe.

In many ways, these developments in Poland can only be understood if they are considered in the context of national revolution. In fact, there are eerie parallels between the events of the past year in Poland and the Russian Revolution of 1917.

In his classic book on the Russian Revolution, "10 Days That Shook the World," the American reporter John Reed recounts many scenes that could be vignettes from life in Poland today. He writes, for example, about women standing in food lines before dawn, of official corruption, of speculators taking advantage of shortages to pile up fortunes, of the hundreds of thousands of political pamphlets and of the atmosphere of intensive debate.

Naturally there are big differences between Poland in 1981 and Russia in 1917. Nevertheless, the revolutionary comparisons here remain important.

Recently, for example, a prominent sociologist, Jan Szczepanski, wrote an article for the weekly magazine Polityka outlining a few textbook theories of revolutions, and some remarkable insights emerged.

The first was that revolutions usually result from economic difficulties and provide "irrefutable evidence of the degeneration of the country's administration." In their early stages, however, they only add to the chaos, and attempts at economic reform are virtually impossible to implement.

As a result, "the revolutionary masses" grow more radical, and a natural process of polarization occurs as some revolutionary leaders try to voice the popular grievances while others begin to withdraw.

Both the masses and their leaders may feel strong enough to seek radical solutions. Some revolutions take place gradually, with the authorities forced to make one concession after another. The takeover of power is then a mere formality provided it does not involve any international interference.

Sometimes, however, revolutionary movements fall into their own traps. One is what Prof. Szczepanski describes as "naive democracy," in which obsession with democratic rules prevents the emergence of an effective leadership. Another occurs when the movement gets carried away with its own emotional but impractical slogans.

All these traits are evident in the Polish revolution. Szczepanski ended his article by summarizing two extreme solutions. One was that the intransigence of the two sides would lead to "a blockage closing minds to agreement and compromise even when these were by no means impossible to reach."

At some moments during a revolution, however, the interests of the leaders on both sides grow similar as all are equally threatened by uncontrolled developments. In this case, it may be possible for them to join to tackle the popular discontent.

Such a solution, Szczepanski adds, "requires imagination and cool reasoning, which are hard to come by during a revolution, both among the authorities and the revolutionary leaders."