Voters in this shattered country will go to the polls Sunday to choose Haiti’s next president, pushing past mounds of earthquake rubble and months of political turmoil to finally pick someone who can steer the nation’s rebuilding effort.

Or at least that is what is supposed to happen.

Haiti’s first round of balloting in November was a disaster of the man-made variety, when Haitians arrived at polls only to find their names missing from voter rolls, or candidates’ supporters crowding the precincts. Some ballot boxes were dumped, others were stuffed, and Haitians rioted, plunging the process into a crisis that was resolved only through assiduous intervention from foreign monitors.

Things are supposed to be smoother this time around. But following the dramatic return Friday of exiled former president Jean-Bertrand Aristide, no one is sure how Sunday’s runoff vote will play out.

From an original field of 19 candidates, two remain: a demure, matriarchal former first lady and university professor, Mirlande Manigat, 70, and a raffish, swaggering pop star, Michel “Sweet Micky” Martelly, 50.

Martelly appears to have the most momentum in the race, waging a vigorous, well-financed campaign that has at times resembled a concert tour, with the slick advertising to match. His ubiquitous pink campaign posters, featuring his smiling visage and gleaming cranium, are stamped with the symbol of a bull — an appeal to rural voters — and his catchphrase “Tet Kale” (Bald Head).

As a popular kompa singer, Martelly was famous for dropping his pants on stage, mooning audiences, and dressing in drag — or sometimes a diaper. In widely circulating Web videos, he admits to smoking crack as a young man, and the Miami Herald reported this month that he defaulted on U.S. bank loans totaling more than a million dollars, for three South Florida properties he lost in just over a year.

But he has proved to be an adept campaigner with a knack for crossover messaging, reassuring elites with pro-business promises and calls to bring back the Haitian army, while cultivating a populist image among Haiti’s poor as an unpretentious outsider who will jolt and jive their country out of the doldrums.

“People see me based on an image that is one image I decided to sell in the past as an artist,” Martelly said Saturday at the Karibe Hotel in the hills above downtown. “My goal is not to be president but to bring results and change the system,” he said. “Why do we have hundreds of millions lent to Haiti but nothing being done?”

His opponent’s demure personality could not provide a greater contrast. She presents herself as the more dignified, mature alternative, a figure who might nurture Haiti through its earthquake trauma and deep economic divisions. Her backers have spray-painted the phrase “Ban Man Man” all over this city: “I want my mother.”

Attempts to reach Manigat were unsuccessful.

Aristide could be the wild card. He has not endorsed either candidate — both are former opponents — but Manigat stands to gain more from Aristide’s support, especially among Haiti’s poorest and most desperate, with whom Martelly has developed a following. When Aristide arrived here Friday, banners went up saying, “My mother is here already. Welcome home Father.”

“I am 100 percent for Aristide, so I will vote for Manigat,” said Andre Jean-Pierre, who wore a Manigat T-shirt Friday night in the city’s Croix-des-Bouquets neighborhood for a last campaign rally, which was broken up by bands of pink-clad Martelly supporters beating drums and zooming their motorcycles in the streets.

At a Martelly concert and rally downtown last week with celebrity rapper Wyclef Jean, amid thousands of fraying tents and bogs of reeking sewage, Chery Rafael said: “Our country is broken, but Martelly will fix it.” Just then, dancing girls passed by on the back of a huge truck with glowing, billboard-sized images of Martelly’s face. “I have no job, no money, no life,” said Rafael, whose wife and infant son were killed in the January 2010 quake. “All I do is walk around and sleep in this tent.”

Pierre-Marie Boisson, a private-sector economist here, said that while the candidates’ styles are vastly different, their agendas are not. “They have both promised the moon to the voters,” he said, pledging free education, jobs and housing to a population in which about 1 million Haitians are stuck in squalid homeless camps.

Having raised expectations so high, both candidates will be under enormous pressure to deliver results in short order, Boisson said, at a time of rising global food and fuel prices.

“When you campaign in Haiti, your slogans have to be populist, but both candidates have met with the private sector and will move ahead” to “restore a proper investment climate,” he said. “What is really critical is to complete the election.”