JEAN-CLAUDE DUVALIER, like his father before him, did nothing for Haiti but deepen its poverty and isolation. His departure is an occasion for unqualified rejoicing. But after the celebration, what comes next?

Haiti's friends, beginning with the United States, will have a responsibility to move quickly with economic aid and other kinds of support to give Haiti's people a better chance for stable self-government than they have had for many decades. Holding elections is essential, but it is not necessarily the thing that needs to be done first. Elections in an atmosphere of confusion and fear are not likely to bring Haiti the kind of government that it needs.

While Duvalier & Co. are gone, the dictatorship's enforcement squads are still in the country, leaderless but heavily armed, with much to answer for. Keith Richburg has described in this newspaper the mass graves of some of the regime's victims. There are a lot of scores likely to be settled. It will take time to reestablish the atmosphere of order and personal security in which normal political life flourishes. To establish that atmosphere, and to get the country's paralyzed economy back into operation, is the job of the interim government that has now taken over.

That interim government -- four army officers and two civilians -- is to be regarded as the custodian of the great opportunity now within Haiti's reach. It does not represent democracy. But it can impose a respect for human rights and prepare the transition to democracy and a better life for Haitians.

In that work it will need help -- and is entitled to it. In a country that has suffered chronic malnutrition, the first need is food. The United States can provide it. Next come the other kinds of economic suppot, and here the multinational institutions such as the World Bank have an essential role. The Inter- American Development Bank in particular has both the funds and the skill to make a crucial difference. Haitians need the means to start expanding their own economic production, beginning with agriculture. Then come medical care, for a population with the shortest average life span in the Caribbean, and education, for a country whose departed rulers regarded literacy as a threat to them.

Haiti, through the nearly two centuries since it won its independence, has been trapped in recurrent cycles of violence and despotism. This year finally offers real hope for something better. The outcome must depend, in the end, on the Haitians themselves. But in the immediate aftermath of the fall of President Duvalier, Haiti's neighbors and friends will have a chance to help its people change the tragic pattern of their history.