Once again, Poland has pulled back from the brink.

But as millions of Poles breathe a sigh of relief at the last-minute averting of a general strike planned for tomorrow, they realize that this has been their closest shave so far.

At one point last week, Poland's communist authorities apparently came very near to declaring a national state of emergency. Had this step been taken, it would have meant a final showdown with the independent Solidarity trade union federation -- starting a chain reaction that could easily have culminated in a Soviet invasion.

Even during the strikes last summer, which gave birth to Solidarity, the dangers facing Poland were not as great as during the past few days. It is precisely because the union exists, and because of the national resurgence that has taken place in the country, that the stakes are now higher. So too is the interest of both East and West in the outcome of the Polish political struggle.

Poland's success in avoiding a disaster this time was due primarily to the decisiveness and unity of the country's workers. Other factors making for a sensible compromise were the tactical sense of Solidarity's leader. Lech Walesa, some exceptionally smart infighting by reformers in the Polish leadership, and the moderating influence of the Roman Catholic Church.

The crisis is not over yet. Tonight's provisional agreement between the government and Solidarity representatives raises almost as many questions as it settles. The hard-liners in the party leadership have been blooded by wounding criticism at a stormy Central Committee session, but have not been entirely defeated. Nobody knows how the Soviet Union will react to the turnaround by the Polish authorities in accepting demands that were previously described as "unjustifiable."

The Polish Communist Party leader, Stanislaw Kania, is still in the position of a political acrobat trying to walk on an increasingly shaky tightrope while being jostled from all sides.

What the events of the past week have proved is that both he and the prime minister, Gen. Wojciech Jaruzelski, remain as committed as ever to solving all disputes by negotiation rather than force. Reports from Warsaw suggest that Jaruzelski threatened to resign last week rather than agree to a state of emergency. This gesture apparently led to the hard-liners in the ruling Politburo backing down -- and eventually being forced onto the defensive.

The past week provided the most formidable demonstration of workers' power yet witnessed in Poland. It was evident in Friday's nationwide "warning strike" which, by all accounts, was a complete success for solidarity. But, even more remarkably, it was evident during the 18-hour Central Committee meeting Sunday when one factory delegate after another got up to criticize conservatives in the Politburo for obstructing change.

Janina Kosorzewska, a worker in a computer factory, openly admitted at the plenum that her party organization had defied the Politburo's instructions by taking part in Friday's strike.

"We knew we were breaking party discipline, but we also knew that we belong to the working class and can never act against that working class," she said.

Virtually all the workers who spoke at the meeting accused party leaders of being out of touch with the opinions of the rank-and-file. It was suggested that the real "antisocialist elements" in Poland are not the dissidents gathered round Solidarity, as the authorities insist, but party apparatchiks interested only in hanging on to their positions and privileges. In a final resolution, Politburo members were instructed to meet with basic party organizations as soon as possible.

This surge of criticism was all the more astonishing because it came from a hitherto docile section of the Polish population. In the past, workers have been elected on to the Central Committee as a reward for years of loyal and unquestioning service to the party. Their job was to endorse decisions taken previously by the apparat and provide a cloak of legitimacy to an unrepresentative body.

The revolt of the workers on the Central Committee, in response to pressure from their own party organizations, helped turn the tide toward the reformers. But, despite calls for new elections to the Politburo, it proved impossible to evict the hard-liners from their positions. The meeting ended by passing a vote of confidence in the entire 10-member Politiburo.

What the meeting did reveal was an open split between the moderates led by Kania and the hard-liners grouped around Stefan Olszowski, the Politburo member in charge of ideology and propaganda. Never before have the differences between the two principal currents in the party been so obvious.

In his speech, Kania emphasized his commitment, to settling all strikes by political means. He talked about the need to avoid conflicts with society and the danger of events getting out of hand. He also mentioned the great surge of resolutions from individual party cells criticizing the Politburo and calling for changes in the leadership.

Olszowski, on the other hand, staked out a hard-line position as the defender of "real socialism" -- the catchword used by the Krenlin for its own particular version of communism. He stressed the need to act in accordance with Soviet policies and accused some Solidarity leaders of attempting to seize state power. By identifying himself with Soviet interests, Olszowski made it exceptionally difficult for the plenum to remove him even though he is reported to have expressed a readiness to resign.

The balance between the two factions in the party was reflected in a vaguely worded resolution, which criticized Solidarity but also opened up the possibility of a compromise by calling for incidents of alleged police brutality against union members to be fully explained.

But, in the long run, the most fateful decision could be to hold an emergency congress of the party by July 20. Elections for delegates will begin immediately -- and, under new rules, they will be held by secret ballot with a choice of candidates.

The irony is that, if the congress goes ahead as planned, up to two-thirds of the present Central Committee could lose their jobs.Given the present mood of the party, nearly all the hard-liners would have to go. That leaves them with just under three months to regain the initiative or face political extinction.