GONAIVES, HAITI, DEC. 15 -- On the eve of Haiti's first attempt at holding a free vote since an election-day massacre three years ago, a surge of voter excitement competed with lingering fears that fraud or violence would again cheat this beleaguered country of its chance to choose a government.

To minimize the chance of a new electoral failure, at least 700 international election observers have arrived here, including former president Jimmy Carter, representatives of the United Nations and the Organization of American States and a White House delegation.

But fears of interference by the 7,000-member Haitian army or by allies of the deposed Duvalier dictatorship that ruled for 29 years continued to cast a pall on the elections for president, legislators and local officials. The last attempt at free elections, in 1987, was scuttled when gangs of unidentified men believed to belong to the Ton-Tons Macoutes, the Duvaliers' militia, shot and hacked to death more than 30 people standing in line to vote.

"We don't know what to expect on Sunday," said Fritz Longchamp, director of the Washington Office on Haiti, an independent group that monitors Haitian politics and human rights. "The confusion is hanging over our heads like the sword of Damocles."

The apparent frontrunner for president, the Rev. Jean-Bertrand Aristide, is a folk hero among poor Haitians, for whom he has long been a lonely, populist voice against this country's tiny class of military and political rulers. Suspected Duvalierists have tried to assassinate him several times and many Haitians, noting Aristide's survival, believe he has mystical powers.

Jean-Claude "Baby Doc" Duvalier fled into exile in 1986, ending a dictatorship begun in 1957, when his father, Francois "Papa Doc" Duvalier, became president in a disputed election. But his partisans continue to hold power and wield influence at every level of government. The Duvalierists have threatened to derail the elections and prevent Aristide from taking power.

"It's impossible," said Zacharie Delva, a onetime leader of the Ton-Tons Macoutes,. "There will be no Aristide tomorrow."

But the 37-year-old Roman Catholic priest -- an accomplished linguist, a student of psychology and a fiery orator who likes to compare his life to that of Jesus Christ -- has an undeniable appeal.

In the town of Gonaives, in Haiti's rice-producing Artibonite Province, scattered interviews suggested that Aristide would be difficult to defeat.

"Everybody's for Titid," said Monique Ervine, a rice wholesaler, using the affectionate nickname that means "tiny Aristide."

Another woman in the town's marketplace agreed. "He's honest, and he's for a change," she said.

The only other candidate among the 11 presidential contenders who seems to have significant support is Marc Bazin, a former World Bank official who has campaigned for Haiti's presidency since the aborted 1987 elections, in which he was seen as a leading candidate.

In Gonaives, several Aristide campaign workers reported that Bazin officials were offering to buy registration cards from voters for $6.50 -- about three times the daily minimum wage in Haiti. Aristide supporters also alleged that a local army commander was organizing rural precinct captains to get out the vote for Bazin.

The reports could not be verified, and Bazin has denied such improprieties in the past. But it was clear that a pervasive and growing fear of Aristide's candidacy had led Duvalierists to rally around Bazin as the apparent best alternative to defeat the priest.

"I encourage everyone I meet to vote for Bazin," said Herad Simon, a houngan, or voodoo priest, near Gonaives. Houngans, who are influential local figures in Haiti, were important backers of the Duvalier regime.

Henry-Claude Moise, the Duvalier-appointed notary public of Gonaives, dismissed Aristide's apparent popularity. "People talk about Aristide, but most of his supporters don't even have voter registration cards," he said. "Most of them are kids and people who didn't have time to register."

Moise said that most of Bazin's backers were registered, but he offered no proof for his assertions.

In recent weeks, Bazin has seemed to court the Duvalierist vote, promising in at least one appearance that he would not persecute allies of the old regime. An alliance between Bazin and the Duvalierists would be a marked change for Bazin, a political centrist and technocrat who gained a reputation as Haiti's "Mr. Clean" for resigning as Jean-Claude Duvalier's finance minister in disgust over government corruption.

Duvalierists have charged that the elections are unconstitutional and rigged. Roger Lafontant, the self-proclaimed leader of the Ton-Tons Macoutes, on Friday urged Haitians not to vote.

But Nearly 3 million Haitians, or some 90 percent of eligible voters, have registered and most observers expect a large turnout.

"Since {Haitian independence in} 1804, the people have never really brought any leaders to power," said Paul Latortue, an agricultural specialist. "But this time, the people are in charge."