WARSAW, NOV. 21 -- There are two Lech Walesas running for president of Poland this fall, or so it often seems. They have different campaign posters. With the election four days away, many Poles are wondering which is which.

The first Walesa is the lean, young hero of the Gdansk shipyards, winner of the 1983 Nobel Peace Prize. His posters show the familiar face with flowing mustache. It is this Walesa, Lech the Good, who has stirred his countrymen by telling them to ask not what their country can do for them, but what they can do for their country. This is the Lech whose political cunning and courage showed Poland the way out of communism.

The other Walesa is a more recent incarnation. In this Walesa's posters, the face is bloated, the gaze is cold and the mustache trimmed so severely that vandals have been inspired to ink in a slanting, Hitler-like hairline and, occasionally, a royal crown.

This, his critics insist, is the real Walesa, Lech the Terrible, the man some old allies now call an incipient demagogue, drunk with ambition and ego.

Walesa has been ahead in public opinion polls throughout the campaign for Poland's first popular presidential election, although the latest government-sponsored survey shows his support ebbing over the last week from a 35 percent favorability rating to 28.

In his bid for the office, Walesa has turned in some controversial performances, alienating old allies and driving a wedge into the Solidarity movement's alliance of workers and intellectuals.

He has called back-alley rumors that Jews secretly run the government a "misunderstanding" to be blamed on a "vague" system, adding: "When we introduce a clear system of government, everyone will know who is who and where he comes from."

Walesa's critics also blame him for introducing coarse, even brutal language into Poland's new and fragile democracy. At his rallies, campaign banners warn: "Get lost, government dimwits, a new steward is coming!" Walesa has castigated the new government as too soft on communism and has vowed to "take an ax" after old Communist elites and new ones in the Solidarity government that he helped elect just a year ago.

Old Solidarity allies also say candidate Walesa now routinely disparages the achievements and sacrifices of the intellectuals who founded the Solidarity labor union and forged it into a national movement. He has referred to the lawyerly Mazowiecki, whom he nominated as prime minister last year, as feeble and incapable.

Campaigning recently in the gritty textile-manufacturing city of Lodz, Walesa lashed out at two eminent artists and Solidarity supporters, novelist Andrzej Szczypiorski and filmmaker Andrzej Wajda, both now senators, who had criticized him on television.

"When I listen to them, I really wonder if they shouldn't be put over someone's knee and given five whacks!" Walesa said. "All of these politicians should be banished from the television sets immediately! Let them not continue telling you this bull about me!"

Poles have grown accustomed to Walesa's often contradictory speaking style -- known to his Solidarity colleagues as "I am for, and even against" -- and have learned to take his words with a grain of salt. But for some listening in Lodz, the fleeting references to physical threat and censorship were disturbing.

"Of course, I know he doesn't mean it literally," Szczypiorski said later. " . . . But because he lacks imagination, he doesn't realize that some people will take it seriously. After 45 years of communism, you can't talk about censorship and swatting people. . . . This kind of talk can trigger hatred."

Some former Solidarity allies also worry that Walesa has the instincts of an autocrat. He has said that as president he expects to bypass parliament and rule by decree. "There will be too much Walesa," he said. "That is why some are afraid."

In parliament, Walesa's forces now dominate the divided Solidarity caucus, recently forcing out caucus leader Bronislaw Geremek, a supporter of Mazowiecki. Walesa's parliamentary whips are tough, and they keep score. "People are afraid not to support Walesa," said a sociology professor who backs him. "They do not fear Mazowiecki."

In an essay entitled, "Why I will Not Vote for Lech Walesa," former adviser and Solidarity comrade-in-arms Adam Michnik has called Walesa a danger to the nation, a charge that Mazowiecki, who until now had refused to criticize Walesa, repeated this week.

"Walesa has qualities that made him the leader of millions-strong Solidarity but disqualify him as president in a democratic state," Michnik wrote. His "political ideal is a job where he holds all power and bears no responsibility."

Walesa's strongest support is thought to be among the country's millions of industrial workers and small farmers, who together make up the majority of the work force.

Bouncing around the country in his Volkswagen mini-van motorcade, Walesa portrays himself as the defiant little guy, the outsider running against old Communist and new Solidarity cliques in Warsaw.

His vow to sweep the government free of former Communists plays directly to the ambitions of the second- and third-tier Solidarity activists who were left behind when the senior Solidarity advisers -- Mazowiecki and others -- moved to Warsaw. It is the former who lead the new Center Alliance party and who expect to fill the jobs that Walesa creates by sweeping the Communists away.

Walesa's message to workers is that they will not be left out of Poland's capitalist revolution, a powerful promise at a time when only old Communist managers and illegal money changers seem to have the cash and know-how to take advantage of new opportunities.

He has promised to take a complicated reform process and shake it by the lapels. "Today, when we are changing the system," he has said, "we need a president with an ax -- a determined, firm and simple man who won't beat around the bush."

But critics say Walesa is making promises he cannot keep. His election platform, released last week, calls unemployment a "transitional problem," and at several steel mill rallies he has promised workers that they will not be fired until new work can be found for them. Mazowiecki's platform calls unemployment "inevitable." It is already at 1 million, with privatization of state-owned factories barely begun.

Walesa's defenders argue that if not for his boldness last year -- when he pushed for a Solidarity share in government while Mazowiecki and others hung back -- Poland would still be run by Communists.

They point out that however incendiary his rhetoric, Walesa usually pulls back in the crunch. And they say that Walesa did not position himself as an outsider, insulting "eggheads" in Warsaw, until some Solidarity intellectuals in parliament began suggesting that a former electrician with a vocational school education would be an embarrassment as a president.

This week, with the polls showing him comfortably ahead, Walesa has softened his rhetoric and begun sounding more presidential. Most of the differences between his economic program and Mazowiecki's seem to have evaporated.

But the image of the emperor's crown may not fade as quickly. "You cannot take everything he says seriously," said Sen. Szczypiorski. "But if you cannot take him seriously, then how can you contemplate giving him the highest office of the state?"