The annual carnival crowd surged past the gates of Haiti's well-guarded presidential palace a few days ago in a deafening cacophony of electronic sound. Inside the grounds, visible to all, the portly "president-for-life of the republic," Jean-Claude Duvalier, 28, and his girlfriend roared back and forth across the lawn on his 1000cc Suzuki motorcycle.

After awhile, he parked the bike near the railings, perched himself on a car and watched the crowd go by. Possessed by the music, few people seemed to notice him. It was not something that would have happened to his feared father, Francois (Papa Doc) Duvalier, before his death in April 1971.

Government officials, entrenched after 22 years of bloody and sometimes precarious rule by the Duvalier family, stress that such scenes are the norm. But observers say that Haiti, whose six million people are the poorest in Latin America, is nearer to real and perhaps violent change than at any time since the Duvalier family came to power in 1957. The prospect obviously concerns the United States, which has been applying pressure on the government to end some of the more repressive masures, and which has a new interest in stability in the Caribbean.

"We are living on a barrel of gun-powder," said Gregoire Eugene, the leader of the Christian Democrat Party. The party, which was formed eight months ago, was the first opposition that the government allowed in 20 years.

For the past six months, the government, confused and sometimes divided by an unprecedented growth of political dissent, has followed a stop-and-go policy of repression and liberalism.

The leader of another centrist party, Sylvio Claude, is in jail after his party headquarters was smashed by police. Other dissidents, some of whom were caught singing antigovernment songs, have also been jailed.

Sixty thugs, reportedly organized by two government ministers, violently broke up a meeting of 6,000 people here three months ago.

The president of the small Haitian Human Rights League, Gerard Gourgue, who was conducting the meeting, was severely beaten along with several foreign diplomats, including one American.

Yet the government suspended a Draconian new press law after much public criticism. Bowing to years of international pressure, it also set up an official human rights office, although the department will have no power.

"The danger is still the same," Gourgue said. "No one has any guarantees."

Yet the dissent grows. It is not so much an open rebellion led or channeled by politicians such as Eugene, as it is a quiet revolt by the young, better-educated middle class. Since the elder Duvalier died, this new bourgeoisie has grown prosperous from the money pouring into the country in the form of new foreign banks. American-backed light industries and the opening of hundreds of small businesses.

Although the new wealth has given the middle class a greater interest in defending the peace and the status quo, it has also created rising expectations that the Duvaliers do not seem to be meeting. The government and the established merchant class are little inclined to take part in the new investments.

Despite a still high level or corruption and financial scandal, the gavernment has so far not done too badly meeting the demands. In eight years, paved roads, phones, electricity, a deep-water port and other economic plums have been fed to the new middle class in the capital. The proportion of young technocrats to politicians has risen. But these advances have only brought new conflict and further demands, which are now spreading beyond the middle class.

There have been revolts by workers against the official trade unions for the first time in decades. But with minor concessions, the government has so far been able to hold control.

The country's young journalists have reached a blank wall of poverty, which prevents the expansion of the dissident press and forces many of them into the new government radio and television system, where official control has recently been increased.

Even the long-silent Archbishop Francois Ligonde, appointed by Papa Doc as the first black head of the Catholic Church in Haiti, has been speaking up against injustices recently.

U.S. Officials have encouraged the dissidents in the hope of softening official Haitian policies and have kept the government under control with foreign aid grants that make up Haiti's budget. But the new Cold War tensions caused by crises in Iran and Afghanistan and the fading of the American human rights stance have dismayed the dissidents.

"We feel alone now," Gourgue said. "Democratic groups no longer have a point of reference. The U.S. has accepted the institution of the life presidency because there has been no mass uprising. There is a certain indifference in the State Department. We are disappointed at the United States, especially at its inaction after one of its diplomats was beaten at the November meeting.

"We rely on outside pressure, but the international organizations support the regime also. Aid has not been cut. Human rights have been sacrificed to U.S. interests."

There is some support among the middle class for an Army coup taking power from Duvalier. Poor conditions in the armed forces have reportedly created sympathy for the dissidents. There have also been clashes recently between the military and the 20,000-strong Duvalier private army, the Tonton Macoutes. Duvalier, in an unusual departure recently, warned the Army to stay out of politics.

"Whatever happens here will be the Americans' responsibility," Eugene said. "U.S. aid has not helped. People are still starving. We must somehow try a new doctrine based on love, but I'm afraid for the future of my country."