NEWS ANALYSIS : Referendum Is Yeltsin’s Big Chance, Big Risk : Russia: He will need massive popular support, tactical skill and political organization to prevail.

After vowing for months to “go to the people” for support in his mission to remake Russia, Boris N. Yeltsin now has his chance. But the April 25 referendum approved by Parliament is full of risks for Russia’s first popularly elected president.

The next four weeks will determine whether Yeltsin has the popular support, tactical skill and political organization to turn a referendum designed by his conservative foes into a victory that will speed Russia’s transition from Communist rule to a market economy.

To achieve this, he must persuade a majority of the country’s 106 million voters to turn out and give him their confidence, despite a sharp drop in their living standards and a widespread feeling that political quarreling at the top has little to do with their lives.

If he fails, Yeltsin will face even greater pressure from a Congress of People’s Deputies that came close to impeaching him Sunday. Even if he succeeds, the referendum rules are designed to protect the Congress from having to submit itself to the voters before its term expires in 1995.

And across the vast heartland looms another risk: Separatist-minded ethnic republics might vote against Yeltsin or boycott the referendum and use it as an opportunity to break with the Russian Federation.

“The worst possible outcome is that this referendum will not settle anything but will split the country much deeper and make the political crisis more dangerous,” said Oleg G. Rumyantsev, secretary of the Parliament’s Constitutional Commission.

The referendum approved by Congress on Monday will ask voters four yes-or-no questions: whether they have confidence in Yeltsin, approve of his economic reforms, want early elections for a new president and want early elections for a new Parliament.

Congress rejected the formula sought by Yeltsin, which would have obliged him or the lawmakers to face reelection this year if either failed to win a majority of the ballots cast.

Under Congress’ rules, Yeltsin must win approval by half of all voters--not just half of those casting ballots--and it would take the same high number of votes to call new elections.

As both sides began organizing campaign forces, Yeltsin met Tuesday with 150 Parliament supporters and heard conflicting advice on whether to accept those rules or organize his own referendum.

Sergei M. Shakhrai, Yeltsin’s legal adviser, told reporters a separate vote was “the one way out” for the president. But lawmakers who attended the closed meeting said most participants argued that a separate vote would only confuse voters, causing many to stay home.

Yeltsin has indicated he will challenge the referendum rules in Russia’s Constitutional Court, seeking to redefine “confidence” as 50% of those voting and to scratch the question about economic reforms. While “reform” means capitalist opportunity for many in Russia, others associate the word with high inflation, official corruption and soaring crime.

Yeltsin was elected in June, 1991, with 48 million votes, 62% of those cast in a six-man presidential field. Most recent opinion surveys show his approval rating slipping to about one in three. But a poll of 1,314 Muscovites published Tuesday in the newspaper Izvestia said 60% would support Yeltsin in the referendum, 18% would vote against him and 18% would not vote.

His support may not be as great outside Moscow, where political divisions are not as sharp. While tens of thousands of Yeltsin supporters rallied here Sunday, the crowds mustering for him in other cities were far smaller.

Arrayed against Yeltsin is a broad alliance led by the Communists, who are reviving the party that ruled the Soviet Union and claim 600,000 active members today. Having declined to organize his own party, Yeltsin will rely heavily on the Democratic Choice coalition, grouping 90 parties and movements, to launch his campaign.

Until now, Yeltsin could also count on broad executive powers and control of state-owned television and radio to rally public support. Over the weekend, for example, he decreed a doubling of the minimum wage and increased benefits to students, army officers and the disabled.

Russia’s standing legislature, the Supreme Soviet, was quick to pass an identical wage increase Tuesday and claim it as its own idea. But lawmakers have also challenged Yeltsin’s decree-making power and voted to seize control of the state broadcast media; the Supreme Soviet plans to set up a supervisory council to replace Yeltsin’s station directors with its own.

While television generally airs all views in Russia, the government last week forced the director of St. Petersburg’s nightly program “600 Seconds” off the air after he called Yeltsin a fascist.

“Television is the decisive factor in the pre-referendum campaign,” said Gleb P. Yakunin, a deputy who met with the president Tuesday. “People in the provinces don’t get Moscow newspapers. Yeltsin said firmly that he would defend television from a takeover by Parliament. It’s even more important to him now than the army.”

The harshest reaction to Yeltsin’s call for stronger executive authority has come from some of Russia’s 20 scattered ethnic republics, whose leaders fear their own power will be undermined. The Parliament chairman of Tuva, on the Mongolian border, has threatened to hold a local referendum next month on independence.

Some of Yeltsin’s advisers urged against holding a referendum for fear it would speed the disintegration of Russia.