During his one-day visit, Clinton met separately behind closed doors at the upscale Hotel Karibe with top vote-getter Mirlande Manigat, a former first lady, and singer Michel "Sweet Micky" Martelly, a pro-military populist who was earlier this month determined to be the No. 2 finisher in a fraud-ridden, disorganized first-round election in November.
Clinton, the U.N. special envoy to Haiti, said he had no preferred candidate. He said he was careful not to do anything in his role as co-chairman of an interim reconstruction commission to compromise his ability to help Haiti and move hundreds of thousands of homeless people out of encampments on fields and plazas.
"If we can continue to work very hard and speed up decisions - and we plan to do so this year - that will help whoever wins be a more effective president," Clinton told reporters during a news conference after a commission meeting attended by the two candidates.
He expressed confidence that the March 20 runoff is "going to happen on time." The fact that the two candidates met with the reconstruction commission will be "well received by the donor community," he said, "and I think it increases our chance that we will get the money we need to move more people out of the camps."
Many Haitians who have been living in tent camps since the Jan. 12, 2010, earthquake believed they would start getting new homes - or at least sturdier temporary shelters - months ago.
Clinton would not respond to questions about the likely impact of the possible return of former President Jean-Bertrand Aristide from exile in South Africa, saying only that it was a matter for Haiti's political leaders.
Aristide, Haiti's first democratically elected president, was ousted in a violent rebellion in 2004 and left the country aboard a U.S. plane. Speculation that he might come back to Haiti soared after ex-dictator Jean-Claude "Baby Doc" Duvalier stepped off an Air France jet in January in a shocking return after nearly 25 years of exile.
Last week, Aristide's U.S. lawyer traveled to Port-au-Prince and picked up a diplomatic passport for the ousted leader that was issued by the government of outgoing President Rene Preval.
A U.S. State Department spokesman recently said Washington believes that Aristide's re-emergence would disrupt the calm needed for the March 20 vote and warned him not to come back to Haiti ahead of the election.
But Haitian Prime Minister Jean-Max Bellerive said Aristide has the right to return at any time as a Haitian citizen. He said Tuesday he had no clue what the "personal intentions of President Aristide are or other formalities that he will have to resolve" if he leaves South Africa.
Bellerive, the reconstruction commission's co-chairman, said Haiti's government has "had no official communication from the State Department telling us in any way, shape or form that they prefer that President Aristide not come now or be delayed in coming."
In response to a question from reporters after his morning meeting with Clinton, Martelly said Aristide has the right to return to his Caribbean homeland.
"If there is a problem, the justice system will take care of it," Martelly said, standing in a scrum of reporters in the hotel's courtyard. "Right now, we have a second round, and that is what we are worried about."
Manigat later voiced the same sentiments to The Associated Press, saying Aristide has as much right to return as did Duvalier. The 70-year-old law professor added: "Because Mr. Aristide and Mr. Duvalier are not ordinary citizens it is possible their presence might create a problem. But we will have to deal with that."
Campaigning for the runoff election, originally slated for January, is set to begin Thursday. The final vote count - the naming of Haiti's next president - is not foreseen until April 16.