The writer filed this report after arriving in Warsaw from Gdansk.

At the gates to the Lenin Shipyard here, where Solidarity began with an occupation strike in the summer of 1980, there was an eerie emptiness this morning. By acting swiftly on a Saturday night, Polish authorities caught this nation of workers off guard, away from the job, effectively disarming them of the sit-in weapon they had used and threatened to use to enormous advantage several times during the 16 months of social upheaval.

The gates to the shipyard were closed as small groups of Poles wandered up to look through the bars into the stillness.

If the Soviets were to invade, or the Polish authorities to order a crackdown, it had been widely expected to happen on a Saturday night when the factories and shipyards of Poland are generally empty.

Yet Solidarity's leadership, gathered in this Baltic port for a meeting this weekend of the union's 107-man National Commission, appeared strangely surprised when the moment came.

Most of the union's executive council and key advisers were rounded up by Polish police early this morning. They surrounded two hotels in which the union officials were staying and peacefully escorted them into waiting vans, then drove off.

There were rumors early in the day Saturday that Polish militia were massing on the outskirts of this fierce labor town. But union officials seemed to pay no heed, pressing on with a revolutionary agenda.

The series of resolutions that emerged in the end -- calling for democratic elections next year, proposing public referendums on major political questions, and defying a government ban on protest rallies -- clearly marked the open politicization of Solidarity and a full attack on the Communist Party, which has held a political monopoly in Poland for 36 years.

From its inception, Solidarity had been as much about political and social power as economic interests. But the union initially had recognized and observed the fact that essential control of Poland would have to remain with the party for the sake of Soviet concerns -- or Poland's geopolitical situation, as the phrase went.

In fact, union leaders had been reluctant to get involved in matters even of economic control at first, preferring to demand a greater share of economic gains without taking on the burden of co-responsibility with the state for how the economy would be run.

This changed before long, when Solidarity felt stronger and saw the need to push for workers' councils at the factory level -- a democratization of the national economy that would reform the stultified, overly centralized system.

Then, just within the past few weeks, the union leadership seemed propelled into reaching for the country's political reins outright.

The immediate trigger was a paramilitary operation earlier this month against the Warsaw firemen's school to remove cadets who were occupying the building. This was the biggest actual use of government force in Poland since the union's founding, seeming to signal the government's new determination to get tough.

But the real motivations for the union's leap lay deeper.

Before the incident, Solidarity officials were already deeply distressed by the few gains they had been able to achieve during months of negotiations with the authorities on the major questions of economic reform and access to the media. Since the spring, the union could not claim to have won any substantial battles with the state.

The economy was worsening as a result of the continued turmoil in the country and the onslaught of winter, and this seemed to weaken the threat that Solidarity would use a general strike to pressure the authorities for more concessions.

Such frustrations, though, rather than pushing the union toward conciliation, only made Solidarity's militants adopt a harder line. These activists were acutely aware that the authorities had managed to hold them in check for some time. But they had also shed any fears they might have once had about a Soviet intervention or government crackdown.

They were deeply suspicious of attempts by the government to invite their union into a national front of unity.

Further, and this may be the crucial point, they simply had no confidence in the ability of the current authorities to deal with Poland's crisis.

It was time, they believed, to take matters of government into their own hands.

"The government doesn't work," said Ronislaw Gerremek, a writer and key intellectual adviser to Solidarity leaders. In an interview Saturday during a break in the meetings:

"It is not just a matter of good or bad anymore. It simply doesn't work. What we are facing now is not a technical problem, not a problem of finding new solutions to Poland's situation, but a problem of the general structures of power in the country."

Solidarity had fallen to the militants. As the commission meeting wore on, it piled demand upon demand and tactic upon tactic against the authorities, who themselves had hardened and were issuing ultimatums.

The union threatened yesterday to call a general strike if the government passed an emergency powers bill. It threatened a public referendum, which was a new and potentially more dangerous weapon. If the government's version of the bill passed, the union decided to hold protest rallies.

In the past, Solidarity's chairman, Lech Walesa, the one-time electrician who had led the shipyard's strike in l980, had been able to pull union meetings back from decisions that might have spelled its end earlier.

But Saturday, Walesa was unusually reserved though deeply angered, he said, by the course the meeting was taking. In an interview during a break, he said he regarded the ideas of democratic elections as both dangerous and unrealistic.

He said the union should be concentrating on building up workers' councils in factories, practicing economic democracy and forming a political base that way -- rather than pressing for representation on local and national political councils."

Walesa tried one appeal to the commission by having the union's group of experts read a draft of a resolution that urged members to reconsider what they were doing. But the delegates ignored the motion.

His last hope was that the union's political resolutions would not by themselves be enough to provoke the crackdown.

"Such big meetings are rallies," he said. "They never lead to realistic solutions." Walesa disclosed that he was planning to reorganize things by setting up single-issue groups that would become the centers of discussion and compromise in Solidarity, rather than to continue to leave critical union businesss to the volatile and increasingly militant course of large commissison meetings.

Walesa actually had sought out the interview with the Post, saying he wanted to disucss anti-Semitism in Poland. He said he was afraid remarks by about Jews by Solidarity member Marion Jurczyk, of Szcezin, would be used by forces out to destroy Solidarity. He stated that the union would not tolerate anti-Semitic talk and would withstand attempts to use the issue to divide the union and blacken its reputation.

Anti-Semitism, which has a long history in Poland, has been resurgent recently in Solidarity circles. Unsigned leaflets have slurred several advisers thought to have Jewish roots.

But to talk of this when issues were being debated that could mark Solidarity's suspension and perhaps its end seems curious in retrospect. At least it indicated Walesa, along with others in Gdansk Shipyard figured they had more time to work out the nation's problems.

Just before the conference ended at a few minutes before midnight, Walesa took the podium to announce that communications lines to Warsaw had been cut.

He seemed to take an almost jeering delight in informing about something his militant rivals in the union had brought on themselves. All he added was, "The lines might be unblocked tomorrow morning, or might not."