In a heavy turnout this past week involving three out of every four eligible Lithuianian voters - more than 90 percent of them cast ballots favoring independence and democracy. The vote, declared "illegal" by Gorbachev even before the balloting, nevertheless leaves the Soviet ruler in an awkward corner.

It is a corner of his own making - one that dramatically took shape when he sent tanks into the small Baltic country Jan. 13, resulting in the deaths of at least 14 people.Even though Lithuania was originally annexed by Stalin in 1940, its people have continued to look to the West, to Europe, rather than to the East and the Kremlin. They are determined to free themselves, no matter what the cost, and their president, Vytautas Landsbergis, a pedantic music professor, has become a symbol of the resistance.

Meanwhile, Gorbachev continues to flail and flounder in his awkward attempt to stop the Soviet Union from disintegration. In one sense, it seems almost laughable that Gorbachev, who rules a superpower of 286 million people, would be threatened by Landsbergis, whose sliver of land holds 3.6 million people.

But the Lithuanian leader has the moral and psychological advantage in a war of wills that has dramatized the personal differences between the two men while accentuating their political differences.

Since Gorbachev is looking less and less like a reformer, he will probably turn up the heat on Lithuania rather than sit down to negotiate a peaceful resolution. That means the electoral triumph for Lithuanian voters is an ambiguous one for which they may pay a very high price.

If Gorbachev does crack down even more decisively by sending more troops and displacing the unfriendly government with a puppet regime of his own, he would send a chilling message to the other rebellious republics - while being completely discredited in the West.

If Gorbachev still has even an ounce of the expertise and insight that has turned around Soviet and Eastern European history in the past year, he will turn a sympathetic and humane ear to Lithuania's pleas - if only to protect his international reputation.

But that reputation may be the least of his worries. Gorbachev may no longer be in total command of the Soviet Union. The army may be sharing power, if not dictating it. And the issue is further complicated by the fact that Lithuania and the other tiny Baltic states are only part of the problem.

If they break free, it may start an avalanche of other defections - major Soviet states that also have been making ethnic noises about independence. If that happened, the Soviet Union effectively would cease to exist as a nation.

Gorbachev increasingly is in a position where almost any choice about the Baltic states may be his undoing. The Lithuanian election only increases that pressure.