It is the fourth December since the suppression of the independent trade union Solidarity, and Lech Walesa is at home in his apartment here, nursing an ulcer.

He has been excused on doctors' orders from his electrician's job at the Lenin Shipyard. There is no respite, however, from an investigation by a Gdansk prosecutor, daily meetings with supporters and advisers, or the slow, wearing grind of a political struggle in which, Walesa said, "there is no possibility now to have a solution."

It is overcast and cold in Gdansk, and Walesa sits restlessly at a table in his study, chain-smoking cigarettes and sipping tea.

"Maybe it's the weather," he said, staring out the window. But there is no disguising his mood: Solidarity is stymied, and Walesa, its symbol, spokesman and still very active leader, is feeling profoundly frustrated.

"The effectiveness of our work is not very great," he said, with characteristic bluntness, during an interview. "Until now we were fighting with the authorities. Now we are looking for different methods, but we don't have any. If we find some, they must be better orchestrated and better understood."

Above all, this has been a year in which Walesa and thousands of Poles who still support him have begun to see their future as a long, uphill battle to keep the union's ideals alive despite constant repression, the demoralization and apathy of much of the public and the inherent paralysis of an organization committed to nonviolent tactics in the face of a regime that allows no compromise.

"We will not give up," Walesa grimly declared. "Sooner or later my way will win, and the authorities will have to change their attitude." Increasingly, though, the 42-year-old Nobel Peace Prize-winner worries that his own methods have been discredited among frustrated youth and that Solidarity's moral appeals will be overtaken by violence that Walesa no longer feels he can prevent.

"Many times I warned of this possibility, and more and more the possibility is increasing," he said. "I want to be always a man of agreement, but I will not stop other people who see my inefficiency. I am faithful to my ideals, but for others, if they think other methods are more effective, I don't have any more arguments for stopping them."

Solidarity's symbolic and cultural strength is still formidable. Much of its underground leadership has eluded security forces for four years, and thousands of supporters participate in a clandestine publishing industry of a size and dynamism without parallel or precedent in a Communist-ruled country.

Churches around the country filled to overflowing this year for the union's anniversaries and cultural events, which were invariably capped by the emotional singing of Polish hymns by thousands who raised their arms and spread their fingers in Solidarity's victory sign.

Nevertheless, the union's efforts at practical political action have been blocked on every front. Street demonstrations no longer attract widespread support, and an attempt at a national strike in July failed.

"We have losses because of that," Walesa said. "We have good people being arrested, and we need them somewhere else."

Dozens of Solidarity activists, including three of its top leaders, remain in prison despite a recent government release of some political prisoners. Those still free face the possibility of summary arrest and sentencing under a newly sanctioned penal code, or the loss of their jobs through purges, such as one now under way in universities.

On its fifth anniversary last Aug. 31, Solidarity issued a long report on the national situation, and Walesa called on authorities to discuss it. The official reaction was scornful.

In October, the union called for a boycott of legislative elections. Although the government's own figures showed that 22 percent of the people failed to vote -- a high rate for a country with mandatory voting -- authorities loudly proclaimed the elections a success and began a criminal slander investigation against Walesa, who had said that his findings showed that more than 40 percent abstained.

Since the elections, the official position of the government of Gen. Wojciech Jaruzelski is that Walesa and Solidarity are no longer relevant to Poland's political situation. The former leader of an organization with 10 million members, according to the government, now represents an isolated minority that survives only because of its support by "anti-Polish interests" abroad.

As Jaruzelski has hammered at the theme of Poland's "normalization" in speeches at home and abroad, even Solidarity's international profile has begun to erode. As Walesa spoke one afternoon earlier this month, a Radio Free Europe broadcast he had tuned in reported on Jaruzelski's first reception by a major western head of state, Francois Mitterrand of France.

Suddenly, Walesa's name was mentioned: The broadcast had turned to the news of the refusal of former West German chancellor Willy Brandt to seek to visit him in Gdansk during a trip to Poland.

"There are changing attitudes. Some may help us, and some may act against us," Walesa remarked. An aide switched off the radio. "But I know one thing for sure: To solve the Polish problem, it is necessary to have Solidarity."

In Walesa's view, Solidarity's best course in the present situation is to focus on devising its own goals for the country and avoiding confrontations with authorities that sap its strength.

"We have to carry out our plan and not divert our attention to secondary spheres of conflict that are not created by us," he said. "We need peace while working on a solution."

At the same time, Walesa believes that Solidarity and its supporters must remain outside the political system or its institutions, refusing to cooperate with Communist authorities on their terms. "When I go into the system, I want to know what for," he said, "because it's difficult to order someone into a liquor store and then decide you want bread."

His views, however, are no more dominant within Solidarity's scattered, factionalized organization than they were when he headed its 16-month legal existence. Some of the union's activists now favor an organized move by its supporters into officially sanctioned unions, factory self-management councils, professional associations and even the legislature and security forces in order to reshape them from the inside. Others want militant action to disrupt Jaruzelski's rule.

Some of Walesa's own closest associates are skeptical that Solidarity can produce a unified, concrete program for the country.

"The trouble is not the mediocrity of our intellectuals but that such a program cannot be" put forth, said Janusz Onyszkiewicz, a former spokesman for the union. "People were spoiled by the [legal] period because the goals were fairly concrete and it was always established how we were going to achieve them, and when. That's simply not possible now."

In the end, most of the union leaders agree that Solidarity must now wait -- and survive -- in expectation that the authorities' failure to solve Poland's problems without public support will lead them toward another era of liberalization.

Even in the gloom of another December, Walesa leaves little doubt that he has accepted that long, uncertain struggle. "I'm not discouraged," he insisted. "I'm boiling inside. As much as I can and as much as I am able in my health, I will try to uphold the ideals."