AS THE BUSH administration pours billions into reconstruction in Iraq and Afghanistan, a third nation-building effort is precariously proceeding on a shoestring 600 miles from Florida. Early this year Haiti lived through a revolution that resulted in elected president Jean-Bertrand Aristide being transported into exile on a U.S. military aircraft; a day later, 1,800 U.S. Marines belatedly arrived as part of a U.N.-sponsored effort to restore order. Now the Marines have left, replaced by an untested force of Brazilians and other South Americans. Meanwhile, an interim government is struggling to gain control over the country. This week at a Washington conference the United Nations and other organizations will seek $900 million in new funding to jump-start the economy and rebuild shattered institutions. Success might open a modest window of opportunity for the hemisphere's poorest country -- which is why the Bush administration and Congress ought to be doing more to help.

Optimists point to a slight rebound in Haiti's miserable conditions in the last month, following the violence of the winter and devastating floods in June. Electricity and a measure of security have returned to the capital. The interim government, after a shaky start, has drawn up a plan for elections next year, taken steps against rampant corruption and drug trafficking, and won the support of international lenders. Neighboring Caribbean nations, which refused to recognize the new administration because of claims by Aristide that he was forced to leave Haiti by the United States, appear close to changing their position.

Haiti's recovery nevertheless remains precariously weak -- largely because of an underpowered international effort. The small number of peacekeepers in the country -- 2,200, compared with the more than 6,000 that a U.N. plan calls for -- means that large parts of the countryside remain in the hands of armed gangs, some of them led by former members of the since-disbanded army that once ruled the country by force. In the effort to disarm them, the Brazilians have resorted to staging an appearance by their famed soccer team and requiring disarmament as the price of admission.

The new administration's ability to effectively make use of international aid is also open to question -- many donors still remember the experience of the 1990s, when a nation-building program backed by the Clinton administration essentially failed. But foreign officials say the interim government has taken some promising steps to account for spending and ensure that it goes to projects that will have an early impact, such as the creation of 44,000 jobs.

What's clear is that Haiti will have no chance at all unless rich countries, led by the United States, step up. Last month the Bush administration announced $100 million in new aid, on top of the $50 million already in the budget; its total pledge for the next two years stands at $200 million. That is less than 10 percent of what was spent on Afghanistan this year, and barely more than 1 percent of the reconstruction aid voted by Congress for Iraq. Such parsimony is foolish: It only strengthens the odds that the next administration in Washington will find itself facing, once again, a crisis in Haiti.