Solidarity underground's future hangs by a thread

The future of the Solidarity underground is hanging on almost its last thread after two serious setbacks this week. The first is its failure to involve workers in a work slowdown called for Tuesday and Wednesday, the first two days of a week-long ''go-slow'' action. The slowdown was to protest official disregard of a call for talks between the government and Lech Walesa before Aug. 31 - the anniversary of the strike settlement three years ago which paved the way for the founding of Solidarity.

The second is the decision by one of the Solidarity underground's top leaders , to give up the struggle and call on his comrades to recognize the futility of further clandestine action.

Tuesday was a bad day not only for the opposition in Poland in general, but also for Lech Walesa personally. It could mark what apepars to be Lech Walesa's last bid to keep active worker protest alive.

Aug. 23, the day on which an underground group in the Gdansk shipyard had called for the beginning of a weeklong work slowdown, turned out to be the government's best day since it lifted martial law a month ago and offered amnesty and immunity to all underground activists giving themselves up before Oct. 31. (At the Gdansk shipyard, a spokesman said that electrical power consumption was higher than on an average Tuesday.)

The action itself, with Western reporters questioning workers as they left the yard at the end of their shift, appeared never to have gotten off the ground. As of this writing, Wednesday's response was also negligible.

It represents a bigger failure than last November's effort to promote a nationwide four-hour stoppage (which had a poor response) to mark the anniversary of Solidarity's legal registration in the halcyon autumn of 1980. This week's failure indicates that the mood among workers has deepened into a general spirit of resignation and desire for calm instead of purposeless conflict.

Since amnesty was announced last month, 108 clandestine activists (according to official Polish figures) have turned themselves in and have been able to return to their ''normal lives.''

A still worse blow than the go-slow's failure for what is now left of the underground was the appearance on television Tuesday evening of one of its four top leaders, Wladylsaw Hardek. Hardek had been in hiding for the last 18 months, and was a member of the National Provisional Coordinating Commission (TKK). As such, he was a signatory of a TKK statement which only a few weeks ago denounced the lifting of martial law as no more than a propaganda ploy.

[The official Polish news agency said the Krakow police, after talking with Mr. Hardek, had requested the military prosecutor to drop a case initiated against him during the martial law period.]

Hardek's decision is all the more damaging because he represented the big Krakow industrial region, where he was known as the leader of a brief strike at the Nowa Huta Steelworks - the biggest enterprise in Poland, with a work force of 32,000 - in the first days of martial law.

It had been a difficult decision, he said. But he had come to the conclusion that the path ''we initially considered correct'' had brought only losses. Society and the country, he said, needed ''normalization and calm.'' He appealed to his colleagues left on the TKK and to other activists still in hiding to ''think over the purposes of any further activity.''

The failure of the slowdown and Hardek's action present the only major question now left open: What will the TKK, as such, now elect to do?

These latest developments bring Mr. Walesa's future into considerable doubt. His statements and behavior in recent weeks have seemed to reflect his own uncertainties and ambiguities. These are more apparent than at any time since his release from internment ninemonths ago and his subsequent vain endeavors to persuade the authorities to still recognize him as a spokesman for Solidarity, which was banned by the October 1982 law creating the new unions.

On Tuesday Walesa issued an understandably vehement rebuttal of the authorities' more recent and increasingly strident campaign calculated to denigrate him and his standing with the workers. He also denied that he personally had called for a slowdown at the shipyard.

That is so, but he certainly seemed to have endorsed it, after giving workers outside the shipyard a brief pep talk last week. He told them he would be there again on Tuesday. Instead, he left the yard Tuesday by a side entry and, in answer to inquiries about what was going on inside, he said laconically: ''Ask the people.''

Thursday may throw light on the government's next moves: Vice-Premier Mieczyslaw Rakowski is scheduled to visit the yard. Rakowski was the government's negotiator with Walesa over some kind of lasting settlement with Solidarity throughout the troubled year of 1981 right up to the last days, in fact, before the imposition of martial law.

But whatever the vice-premier has in mind for a visit - which could prove of considerable significance for Gen. Wojciech Jaruzelski's ''conciliation'' effort - the former union leader is not - to put it mildly - likely to have any part in it.