Dimming hopes for a return to democracy in Brazil, President Joao Baptista Figueiredo has sent to Congress a set of restrictive election laws that virtually guarantees uninterrupted rule by the present military-technocratic alliance through the end of the decade.

This week he also canceled part of Congress' upcoming summer break for a special session to act on the election package. The congressional session, which is to last through Jan. 15, is the first called by the executive in 13 years.

Figueiredo, the latest of five Army generals to rule since the 1964 military coup, repeatedly has vowed "to make this country a democracy." Since he took office in 1979, his abertura, or liberalization program, has received widespread international acclaim as a showcase attempt to guide a Latin American military dictatorship back to civilian rule.

But the long-awaited election rules unveiled this week are written so as to ensure a government party victory at the polls next November.

As a measure of the sudden reversal, forecasters last month predicted Brazil's opposition parties would win governorship races in 18 of the 22 states. Today, political observers say the official Social Democratic Party will sweep at least 17 of the state races.

"It's a new Pearl Harbor," said Ulysses Guimaraes, a member of Congress and president of the strongest opposition party, the Brazilian Democratic Movement.

"We are facing the collapse of the electoral process," read the official statement of the moderate Popular Party, the second-largest opposition force. "What is planned here is nothing more, nothing less than the strangling of the opposition parties."

"It demystifies the farce of the abertura," commented Luis Ignacio da Silva, Brazil's most popular labor leader and president of the Workers' Party. Last month, a military court sentenced da Silva to 3 1/2 years in jail for leading an "illegal" auto workers' strike. He currently is free while the conviction is appealed.

The new bill prohibits coalitions among the five opposition parties and requires mandatory straight-ticket voting. At the ballot box, Brazilians traditionally have voted first for their local interests. But under the new bill, by voting for a favorite candidate for city council an elector will also automatically vote for state deputy, federal deputy, federal senator, and governor -- all on the same party slate. Not by coincidence, the government party's strength is concentrated at the local level -- with 75 percent of the mayors and 87 percent of the city council.

Both opposition and government officials believe this system of "compulsory coattails" will sweep the government's relatively weak candidates at the state and national level into office. In 1984, this pool of elected officials is to make up an electoral college to choose Figueiredo's successor, whose term will run through 1991.

"The crucial difference between liberalization and democratization is that liberalization entails significant civil liberties -- freedom of association, freedom of the press -- but democratization is the point where higher national positions of government are put at stake in fair elections," said Guillermo O'Donnell, an Argentine political scientist here. O'Donnell is comparing the recent experiences of Spain and Brazil for a project on democratization sponsored by the Woodrow Wilson Center for International Scholars at the Smithsonian Institution in Washington.

"In Spain, the opposition was allowed to participate in the formation of the new regime and the writing of the new constitution," O'Donnell said. "But in Brazil, the military have been reluctant to let the opposition share responsibility."

Indeed, last week, at the same moment that nine opposition leaders were meeting with Brazil's minister of justice to negotiate the final details of an electoral reform bill, Figueiredo called leaders of the government party into his office to announce the preliminaries of his secretly prepared electoral package.

"The only topics we can discuss now are soccer and beauty contests," said Tancredo Neves, leader of the Popular Party, when informed of the new electoral rules.

Last Monday, Alfred Stepan, Brazilian scholar at Yale University was to give a speech on Brazil's democratization before the Overseas Development Council in Washington. Shortly before he walked to the podium, he glanced at a Brazilian newspaper with news of the electoral package.

A paper here quoted him saying: "I had a prepared speech, but now I don't know what to say . . . . This is much worse than the Rio Centro bombing or the resignation of Golbery in its implications for the transition from liberalization to democracy. I don't know what to say."

Gen. Golbery do Couto e Silva, widely considered to have been the chief military architect of restoring democracy to Brazil, was replaced as chief of staff after resigning Aug. 6. Golbery had been under fire from the right since May, when he pressed for a complete investigation of suspected military involvement in the bomb explosion in which one military intelligence officer was killed and another wounded when a bomb they apparently were carrying exploded in their car.

Figueiredo's election bill is assured passage in Congress. If the government's slim majority cannot muster enough votes for approval, a filibuster by the opposition will be futile. In Brazil, all bills submitted by the executive automatically become law after 40 days if Congress does not act on them.

To discipline his party, Figueiredo has threatened to break the mandate of any government congressman who breaks ranks and votes with the opposition. Last month, 10 such defections in the normally rubber-stamp Congress caused a key government bill to be defeated.

That vote was reportedly the first time since 1964 that the government lost its automatic majority -- a result that is said to have led Figueiredo to push through his electoral-law changes.

"Negotiation is back," reported a newspaper headline after the unexpected government defeat in Congress in October.

In September, Figueiredo suffered a mild heart attack, and for the first time in 17 years, Brazil had a civilian president. Vice President Aureliano Chaves took office for 51 days while Figueiredo was indisposed. In 1969, a military triumvirate blocked a civilian vice president from taking control after the military president suffered a heart attack.

During Chaves' interim presidency, he paid a lengthy call on Congress -- the second such presidential visit in 17 years of military rule.