WARSAW -- On the eve of weekend meetings to formalize the split in Solidarity, Lech Walesa is consciously set on dividing the movement he created. The question that hovers over post-Communist Poland is: Why?

The answer from his former close associates, now in the government, is blind ambition unrelated to policy, an analysis shared by U.S. officials. But in an interview with us at Solidarity union headquarters in Gdansk, Walesa gave reasons basic to this country's hope for a future brighter than its tragic past.

''I don't want to run for president, but I'm not going to have any choice,'' he told us. He said that although he would be ''personally defeated'' in the election, such a loss is needed for ''democracy and pluralism'' in Poland to keep a new brand of statism from replacing communism. He called the government's decision to move to capitalism via austerity ''hard on the people, and it's not effective.'' He said Poland may have squandered a ''historic gift'' offered by communism's collapse when the new government was not quick enough in cleaning out Communist bureaucrats.

This is more than a cat fight between Polish politicians. This country is a test tube because communism fell much more rapidly than anybody dreamed, and the Solidarity-run government opted for immediate transformation to a free market.

The intellectuals who run the government plead for time to accomplish this daunting task without the distraction of party politics. Thus, Walesa's sudden return leading an embryonic opposition, which won't help foreign investment, antagonizes former revolutionary colleagues.

Contempt has replaced condescension as the Solidarity intellectuals' attitude toward the former shipyard worker who uses slang and soccer metaphors when he talks politics. ''Lech for president?'' sneers one government official. ''He's a trade union leader.''

The esteemed Bronislaw Geremek, head of the Solidarity bloc in lower house of Parliament, told us Walesa seeks to regain ''lost momentum'' in personal popularity. One longtime friend says Walesa is jealous of Czechoslovakia's President Vaclav Havel. Adam Michnik, editor of Solidarity's influential daily newspaper, suggests Walesa may want to be ''monarch of a post-Communist empire.''

Such talk infuriates the Nobel Peace laureate, who fears his once-shining image will be tarnished in the United States. ''I don't like to look like a fool in the West,'' he told us. ''I'm not stupid,'' he said. ''If I wanted to be elected president, I would seek support from big names'' -- Prime Minister Tadeusz Mazowiecki, Michnik and Geremek. By opposing them, he said, he is sure to lose.

He demanded that Michnik remove the Solidarity insignia from his newspaper because ''we may replace the Communist monopoly with our own. ... In a few years, the whole revolution will be destroyed'' unless, he added, he ''separates'' himself from his old colleagues.

Contrary to claims he has no alternative to the government's ''shock therapy,'' Walesa as a self-styled ''practical man'' opposes the plan drafted by American academicians and put into effect by Polish counterparts. He takes populist exception to grinding down an economy suffering from underproduction, and he wants new enterprises established rather than old ones closed down. Without saying so, he makes a supply-side vs. International Monetary Fund argument.

That sounds like grounds for serious debate, but Poland is new to this. Walesa was overly combative presiding over last Sunday's tumultuous Solidarity meeting (though his aide complained his role was distorted by state-controlled television). If Walesa's allies call Michnik a ''crypto-Communist,'' the editor furiously complained, they are ''pigs.''

Behind such rhetoric is Walesa's track record against the establishment. One Solidarity intellectual, Sen. Janusz Ziolkowski, told us Walesa is ''slightly autocratic.'' But he points out how often Walesa has made the correct political decision when everybody else thought him wrong.