By Nick Caistor
BBC regional analyst
There were many things to celebrate after the first round of Haiti's presidential and parliamentary elections held last week.
Supporters of Mr Preval say he was robbed of an outright victory
After initial confusion around some polling stations, there was little violence on the day of voting.
Haitians turned out in record numbers. Some 63% of the 3.5 million registered voters cast ballots, far more than in any other election held since the Duvalier clan was ousted from power in 1986.
The voters showed a clear preference: Rene Preval, the man who was president from 1996 to 2000 and this time headed the L'Espwa (The Hope) movement.
The candidate in second place, with around 12% of the vote, was another former president, the Christian Democrat leader Leslie Manigat.
But Mr Preval has failed by a small margin to win the presidential contest outright and that leaves Haiti in a dangerous situation, with many unanswered questions.
Supporters of Mr Preval have taken to the streets, protesting that he was robbed of an outright victory.
They say the "international community" - principally the United States and France - does not want to see him back in power because in the past he has been a loyal supporter of President Jean-Bertrand Aristide.
Mr Aristide's supporters claim that the United States and France kidnapped the president at the end of February 2004 and forced him into exile. Both countries have denied the allegations.
The supporters are now protesting that it was similar pressure which prevented Mr Preval winning an outright victory in the first round this time.
Any sign that the US is worried about his return to power could lead to further violence.
Behind this is the biggest unanswered question of the Haitian elections. How many people voted for Mr Preval in the hope that he would bring back Mr Aristide?
When Mr Preval was president from 1996 to 2000, he acted as Mr Aristide's lieutenant, filling in for him because Mr Aristide could not be immediately re-elected.
He was duly replaced by Mr Aristide in 2001, after which there was a rapid breakdown of political stability.
Rene Preval (C) was a close ally of ousted President Aristide
But President Preval's four years in office were a period of relative calm, with some improvements in the Haitian economy, a more or less functioning parliament and efforts to revive local government.
Mr Preval kept out of the political violence of 2003-2004, and in the run-up to these elections has stressed that he is now his own man.
The problem he will have if he emerges triumphant from the second round is if those who voted for him press for an immediate return of Mr Aristide. They could make it impossible for him to govern effectively.
At the same time, if Mr Aristide does return, that would also make things difficult for a Preval government. The opposition would probably boycott parliament again, as it did in 2001-2004, and the political situation could once more quickly descend into chaos.
Another danger is that the opposition will choose to withdraw from the second round and from further voting for the 129 parliamentary seats also being contested.
Even before the first round, some opposition groups had threatened to pull out, claiming that a vote for Mr Preval was simply a vote for Mr Aristide.
If they now seek to undermine Mr Preval before the second round of voting, due in March, they could plunge Haiti back into the widespread violence that led to Mr Aristide's downfall in 2004.
Signs of strain
This danger makes the role of the 8,000-strong UN force (known as Minustah) even more crucial in holding the peace over the coming weeks.
Haiti's army was abolished in 1994 and its 5,000-strong police force has repeatedly shown itself incapable of keeping order, especially in country areas and the slums of the capital, Port-au-Prince.
UN peacekeepers were sent in after Mr Aristide was forced out
There are signs of strain among the countries that have previously backed Minustah.
The Socialist government in Spain has said that it wishes to withdraw its 500-strong contingent from Haiti "in the next few weeks", unless more effort is made to fulfil pledges of aid made by donor countries.
Faced with the confusion after the first round of voting, there have been calls for the United States, which is currently chairman of the UN Security Council, to convene an emergency debate to discuss Haiti.
Any such debate would need urgently to re-affirm the international community's support for the electoral process and for Minustah, and to stress that the international donors who have pledged more than $1 billion (£570m) in aid for Haiti will meet their commitments.
By voting in such massive numbers, the Haitian people have shown that they support the political process supervised by the United Nations.
Their hope of a fresh start with properly elected leaders should not be defrauded as it has so often been in the past.