Johannesburg - Businessman Schabir Shaik faces a verdict today in his appeal against a graft conviction, a ruling analysts say might make or break ANC deputy leader Jacob Zuma's chances of becoming president.

Shaik was found guilty of corruption and fraud last year after a judge found he had a "generally corrupt" relationship with Zuma, a ruling that prompted President Thabo Mbeki to sack the man once seen as his preferred successor.

Prosecutors later charged Zuma himself with receiving bribes in connection with an arms deal, but a judge threw out the case in a humiliating defeat for the state.

Prosecutors say they may issue new charges against Zuma, but this could hinge on whether Shaik's appeal is upheld by the Supreme Court of Appeals in Bloemfontein today.

"If (the appeal) is upheld it creates a new political dynamic. People will believe that the president acted in haste to dismiss Zuma before waiting for the legal process to exhaust itself," said Sipho Seepe, a political analyst at Henley Management College.

"But if it is rejected, it will make things more difficult for Zuma."

Shaik was sentenced to an effective 15 years in prison for corruption and fraud in June 2005.

"Mentally, emotionally and spiritually I have braced myself for the worst possible outcome and internalised possible incarceration," Shaik told a radio interviewer last week.

Zuma has strongly denied wrongdoing and has described himself as victim of a political conspiracy designed to deny him Mbeki's job.

Zuma, acquitted of separate rape charges earlier this year, remains deputy president of the ruling African National Congress (ANC), keeping the popular politician in the race for the party leadership at an ANC congress to be held next year.

The winner of that contest is virtually certain to succeed Mbeki as president in 2009, given the ANC's dominance of South Africa's post-apartheid politics.

"As we approach the most critical year in the short history of our democracy, South Africa faces an extraordinary situation," political commentator Alistair Sparks said in a recent essay. "We have a lame duck president and a lame duck challenger."

With acknowledgement to Reuters and Cape Times.