— Exiled Haitian leader Jean-Bertrand Aristide will arrive here Friday from South Africa, according to his attorney, returning less than 48 hours before a runoff vote in a presidential election that has already been marred by fraud and chaos.

It was unclear what impact the deposed president’s return would have on Sunday’s vote, seen as a critical step toward jump-starting the country’s rebuilding process after the January 2010 earthquake that killed 200,000 people. But U.S. officials have been so worried about Aristide’s disruptive potential that President Obama spoke with South African President Jacob Zuma this week to express his concerns, according to the White House.

Aristide boarded a plane in Johannesburg with his wife, Mildred, the Associated Press reported, and the American actor and political activist Danny Glover. “The great day has arrived!” he said in Zulu, a language he studied in South Africa, the AP reported.

Haiti’s attempt to elect a successor to outgoing President Rene Preval, a former Aristide ally, has been a process as shaky as this city’s cracked buildings. The first round of voting in November was plagued by cheating and widespread voter disenfranchisement, leading to a political crisis that international observers had to sort out through delicate negotiations.

That fragility has foreign observers and many Haitians wary of Aristide’s return so close to Election Day. The priest-turned-politician was the country’s first democratically elected leader in 1991 and remains a revered figure among Haiti’s poorest.

Aristide’s critics, though, say he became increasingly corrupt and despotic before a 2004 rebellion that ended when U.S. officials flew him to exile — an event he later denounced as “a kidnapping.”

Aristide has said he will stay out of politics and wants to return to teaching. But few believe him — not his supporters and certainly not his adversaries.

Aristide’s arrival is expected to stir the country far more than that of former dictator Jean-Claude “Baby Doc” Duvalier, who returned to Haiti in January after 30 years of exile in France. Duvalier now faces charges of corruption and embezzlement, but his presence here has mostly been met with a shrug by Haitians, many of whom are too young to remember his rule.

Both of Haiti’s presidential runoff candidates are former Aristide opponents, but if Aristide signals support for one of them, he could tilt the contest. The vote Sunday sets popular singer Michel “Sweet Micky” Martelly, 50, against Mirlande Manigat, 70, a university professor and former first lady.

At a raucous campaign rally Wednesday night in front of a gas station in this city’s Petionville neighborhood, Martelly said in an interview that Aristide had a right to return home, but that he thought the former president was “trying to create a distraction” for his own political benefit.

“He’s just coming back to create instability,” Martelly said.