HAITI SEEMED in the past several weeks to be sliding toward anarchy. Now the head of the provisional government, Gen. Henri Namphy, has tried to generate a sense of orderly democratic progress by announcing a rigorous timetable extending over the next 20 months. A constituent assembly is to be elected in October, and it is to write a constitution that should go to referendum next winter. Under it a president would be elected in November 1987, and take office the following February. A firm schedule is a necessary step, but it is probably not sufficient in itself to achieve stability.

Haiti's terrible poverty feeds a sense of desperate impatience that is going to be extremely difficult for its temporary government to control -- particularly in a country with a total absence of democratic experience. Its history has been a repetition of short periods of chaos interspersed with long periods of one-man rule. Owing to repressive and exploitative government over the years, Haiti remains the least-developed country in the Caribbean. Incomes average about one-fourth those in Jamaica or the Dominican Republic, to cite two close neighbors. Bad government has perpetuated extreme deprivation, and now extreme deprivation threatens to perpetuate bad government. How is the cycle of violence and despotism to be broken?

The provisional government is under attack from both right and left. People who held politically protected franchises and monopolies under the Duvalier regime are working to preserve them. It seems clear that they are instigating some of the rioting. At the same time the government, in its desperate effort to keep spending under control, has closed some dramatically unprofitable publicly owned plants. People who have lost jobs, or fear losing them, have joined other demonstrations. Gen. Namphy's timetable for elections will require a great deal of political organization to be accomplished very rapidly, but it may still be too slow to provide the kind of responsive daily government that Haiti needs immediately. The social conditions that support the development of democracy -- more education, better health services, a rising standard of living generally -- can be accomplished only over time.

But while the basic choices are up to Haiti's people, American assistance this year can make a difference. The United States has shipped grain to Haiti since the revolution, but otherwise there has been no increase yet in American aid. The reason is the budget squeeze here in Washington. The cuts in foreign aid are doing substantial damage to American interests abroad, and need to be reconsidered. The provisional government is entitled to greater support in the months immediately ahead while the processes of democracy and economic development begin to work.