U.S. troops are heading another peacekeeping mission, this time in Haiti, after President Jean-Bertrand Aristide resigned Sunday and fled to the Central African Republic.

The immediate need is to stabilize the Haitian capital, Port-au-Prince, against rampaging looters and armed gangs, but even after order is restored, constitutional government in the Western Hemisphere's poorest nation still will hang by the thinnest of threads.

U.S. Coast Guard cutters stationed off Haiti's shores reveal our strong national interest in seeing that Haitian mobs do not send a new wave of desperate refugees surging toward Florida.

U.N. Security Council members and Western Hemisphere states need to recognize that nation-building in Haiti will require starting over almost from scratch and making long-term commitments, if Haiti is ever to become known for exports other than refugees.

Secretary of State Colin Powell expects about 1,000 U.S. troops will be deployed there - well short of the 20,000 it took to put Aristide back in power in 1994 after he was deposed the first time. Late Sunday, the U.N. Security Council authorized an international force for three months, after which troops from the United States, Canada, France, Brazil and Chile would be replaced by U.N. peacekeepers.

Haiti has been a basket-case nation for decades. The unemployed there total about 63 percent. Haiti's best hope is constitutional government and a market economy. Aristide was the first constitutionally elected president, but in recent years he grew more authoritarian and uncompromising. The former radical Roman Catholic priest used his own gangs of armed enforcers.

The European Union and the United States suspended financial aid after Aristide's party swept the 2000 legislative elections with what was believed a crooked count. That aid-freeze and Aristide's many broken promises made his end inevitable.

Last week, anti-Aristide rebels controlled half the country and were closing in on the capital. He wisely took the U.S. offer of a one-way trip into exile and spared his people more bloodshed. At least one of the rebel leaders headed government death squads in 1991 when the Haitian military ousted Aristide the first time.

At the moment, with U.S. Marines in the wings, Aristide's opponents say they will not topple a new interim government headed by Haiti Supreme Court Chief Justice Boniface Alexandre. Alexandre is following the constitution and reportedly is honest, but unfortunately, Haiti's constitution calls for him to be approved by parliament, which hasn't met since early this year when lawmakers' terms expired.

As in Iraq, the U.S.-led international force in Haiti needs to follow through and see that it creates a professional police force and solidly establishes other democratic institutions. Only then can the former slave nation end its cycle of ousted dictators and take its rightful place in the trading bloc of the Americas.