Lithuanians Cast Historic Ballots : Separatism: Opposition candidates running well. They will have a mandate to secede from the Soviet Union.

While the results of Saturday’s historic elections in avowedly separatist Lithuania won’t be final until Monday, a twofold mandate to whatever new government emerges is already clear: Devise an unprecedented withdrawal from the Soviet Union, and determine how to fight back if Moscow resists.

Turnout was brisk on a sunny, spring-like day, and early returns indicated that candidates endorsed by Sajudis, a mass reform movement, apparently are destined to become the most important political force in the republic’s new Parliament.

At least six legal parties, plus the Sajudis movement, participated in the vote, which was to elect a 141-member Parliament.

In unofficial returns compiled by Sajudis early Sunday, candidates the group favored won 47 of 52 districts tallied.

The reformed Lithuanian Communist Party won 12 seats, including eight in which it was allied with Sajudis and four in which it competed with Sajudis.

Among the reported Communist winners was party first secretary and Lithuanian President Algirdas Brazauskas. He led Lithuania in December when it became the first of the 15 Soviet republics to legalize non-Communist parties.

Since more than 80% of the candidates, including most Communists, ran on platforms calling for independence from the Soviet Union, there was never any doubt about the top issue on the new legislature’s agenda. And for tactical inspiration, politicians have been brushing up on the works of such past authorities as Prince Machiavelli and Mohandas K. (Mahatma) Gandhi.

Sajudis Chairman Vytautas Landsbergis said that there are two possible scenarios for affirming Lithuanian independence.

Under what he terms the “decolonization model,” Moscow and the new government in Vilnius would negotiate a staged separation, complete with treaties defining their future economic, security and other relations.

“This would be done, knowing in advance the date for independence, determining it by an international agreement,” he said.

If Moscow refused to negotiate, Landsbergis said that a second scenario would be for Lithuania to “reclaim our sovereignty . . . in the face of harsh confrontation.”

Such action might come in the form of a parliamentary reaffirmation of Lithuania’s independence between the two world wars or a national referendum. The latter would be a face-saving formality for Moscow, which has included provisions for such a vote in draft legislation covering conditions under which its republics could secede.

In either case, Saturday’s parliamentary elections were a necessary first step.

Seven political parties fielded candidates in the Soviet Union’s first genuine multi-party elections since shortly after the Bolshevik Revolution of 1917. Thirty percent of the candidates ran as independents.

Sajudis, which is not an official political party, endorsed mostly independents, although it also backed 32 reform Communists and a few candidates each from the Social Democratic, Democratic, Christian Democratic and Green parties.

But even with Sajudis backing some of its candidates, the Communist Party could lose a parliamentary majority for the first time in Soviet history.

And even if the Communist Party keeps a nominal majority, it will share power in a coalition Cabinet made up mostly of Sajudis-approved officials. Preliminary work on forming the new government began weeks ago under the auspices of a so-called Interim Lithuanian Political Consultative Council.

Separately, a Commission for the Re-establishment of Lithuania’s Independence has been preparing suggested agendas and position papers for the new government to use in formal negotiations with Moscow.

After 50 years of enforced union, achieving even a friendly divorce will be no easy matter. Lithuania is already preparing its own currency, for example. But many questions remain, among them: Should there be a formal frontier, with guards on the Lithuanian side of the border with the Soviet Union?

“The question of an army is the most complicated,” said Kazimiera-Danute Prunskiene, a deputy prime minister and a member of both the Lithuanian Communist Party’s reform leadership and of the Sajudis governing council.

The Sajudis platform calls for recognition of Soviet troops stationed here as members of a “foreign army” and for immediate negotiations to fix a date and conditions for their withdrawal.

Lithuania is host to 25,000 Soviet troops as well as several Soviet army bases, and the navy has important bases on the republic’s Baltic coast.

There is also the issue of Lithuanians serving in the Soviet military. As many as 8,000 have destroyed their draft cards in recent weeks, and the old Parliament adopted a resolution obliging the republic to defend deserters against courts-martial.

The KGB security service is another potential sticking point. Republican leaders want to transform the service into a servant of Lithuania instead of the Kremlin.

A senior party source who requested anonymity said there is already an agreement with Moscow to replace the current head of the Lithuanian KGB soon. But while Moscow has said it would accept a depoliticized KGB, it holds that it cannot agree to an independent service in Vilnius.

Reordering economic relations between Moscow and an independent Lithuania will take at least five to seven years, even if everything goes smoothly, Prunskiene said in an interview.

The Kremlin’s draft legislation on secession would require a republic to compensate Moscow--a position that raises Lithuanian hackles.

“Looking at the immediate past, we don’t owe Moscow anything,” Prunskiene said. And going back farther, it is the Kremlin that has piled up the debts, she asserted.

Lithuanian leaders are counting on a presumption that Soviet President Mikhail S. Gorbachev will ultimately let Lithuania go its own way rather than crack down and risk tarnishing the goodwill that he has generated in the West through his reform programs.

But agreeing to genuine independence for Lithuania would set a precedent for other restive Soviet republics.

If Moscow stonewalls on negotiations, Lithuanian leaders say, they plan a campaign of nonviolent civil disobedience.

“We are studying the experience of Gandhi in India and South Africa; we are studying the methods used by Andrew Young and Martin Luther King Jr., especially in Georgia,” said Algimantas Cekuolis, an editor and holder of one of Lithuania’s seats in the Soviet Congress of People’s Deputies.