SOUTH Africa’s Constitutional Court will decide on an appeal questioning former President Jacob Zuma’s eligibility to run in this month’s election, a race that could tilt the balance of the parliament and determine the country’s next leader.

The court in Johannesburg is on Friday hearing the appeal filed by the country’s election body after a lower court ruled that Zuma could run for office.

Earlier, the Independent Electoral Commission (IEC), barred Zuma from contesting the May 29 polls.

Zuma, 82, is fronting a new opposition party that has become a potential disrupter in the general election.

While his party, uMkhonto weSizwe (MK), is not expected to win enough votes to return the former leader to the presidency, it could cut into the vote share of the dominant governing African National Congress (ANC) party, and determine who will be the country’s next leader.

In the South African constitution, the president is elected by members of parliament.

The IEC had argued that the corruption-tainted politician should be barred from the race because of a 2021 contempt of court conviction.

The eligibility case against Zuma revolves around the interpretation of a constitutional norm barring anyone sentenced to more than 12 months’ imprisonment from serving in parliament.

The ban lapses five years after the sentence is completed.

The IEC argued the provision applies to Zuma. But Zuma’s lawyers said it does not apply to the former leader, because his sentence was shortened.

Now it is up to the Constitutional Court to decide on the case, which experts say could take days.

The top court is the same body that in 2021 sentenced Zuma to 15 months in prison after he refused to testify to a panel investigating financial corruption and cronyism during his presidency. The head of that panel is now the court’s chief justice.

In their filings, Zuma’s lawyers argued that he and another five judges who sat on the bench that convicted their client should recuse themselves as “tainted by bias”.

Were that to happen, the court would not have enough members left to hear the case.