JOHANNESBURG — If all goes as expected, South Africa will soon be led by a president who is also the defendant in a criminal case, a man accused of fraud and racketeering, legally empowered to select officials who could either drop his prosecution or push it forward.

However one feels about the presumptive next president, Jacob Zuma — and most of the feelings here align toward extremes — his ascension to the top job will test the rule of law in a country often regarded as the democratic anchor of the continent.

Virtually every South African has long wondered what will happen if and when a Zuma prosecution and a Zuma presidency meet at the crossroads. Ticklish days lie ahead.

"It’s hard to see a solution that doesn’t somehow weaken our institutions, not only in the eyes of the country but in the eyes of the world,” said Adam Habib, a political analyst.

Parliamentary elections are scheduled for April 22, and the governing African National Congress will almost surely end up in the majority.

Parliament would then elect Mr. Zuma, the A.N.C.’s leader and a man accused of accepting 783 payments from a convicted briber, as president.

Many here are expecting some sort of expedient political stratagem to keep the nation’s leader from the demeaning spectacle of a trial. Will a newly selected chief of prosecution abruptly decide the case has no merit?

Will an A.N.C.-dominated Parliament pass a measure that outlaws the trial of a sitting president — sometimes referred to as the "Berlusconi solution,” named for the immunity granted Prime Minister Silvio Berlusconi of Italy?

Of late, Mr. Zuma has spoken of his forthcoming trial not as a dreadful burden but as a welcome opportunity to prove his innocence and provide a civics lesson.

"We are going to once again do something that is unprecedented in the country, wherein the president is going to go to court and answer questions and test the allegations against him,” he told Al Jazeera last month.

Mr. Zuma dismissed the notion that he would use his powers to spare himself a courtroom showdown and insisted that if convicted, he would genially hand over the presidency to a qualified A.N.C. colleague.

"And it will be smooth,” he promised. Not everyone was reassured.

South Africa is a nation with enormous problems, among them that familiar medley of poverty, unemployment and abysmal schools.

And yet it is the alleged criminality of Mr. Zuma — and the twists and turns of his protracted case — that dominates public discussion.

This discourse is often uncivil and, some would say, pernicious. Last year, when pretrial decisions went against Mr. Zuma, judges were derided by some A.N.C. loyalists as drunks and counterrevolutionaries. One prominent judge, John Hlophe, faces possible censure for allegations that he tried to influence justices of the Constitutional Court, the nation’s highest judicial forum, in Mr. Zuma’s favor.

Many Zuma supporters consider the case against their leader a political frame-up, or at least an instance of selective prosecution.

"If you arrest him, he will lead us from prison,” said Julius Malema, the head of the A.N.C. Youth League.

"We are not afraid to be led by a president in orange clothes.” He has said he would "kill” for Mr. Zuma.

For the suspicious who believe something shadowy will eventually spare Mr. Zuma, additional evidence seemed to arrive last week.

Schabir Shaik, the wealthy businessman convicted of bribing Mr. Zuma, was released on a medical parole after serving only 28 months of a 15-year sentence.

This leniency is reserved for the terminally ill, but those who are skeptical suppose the new parolee will now somehow handspring back to health.

Through a spokesman, Mr. Zuma denied playing any role in the release, but just days earlier he said that as president he would use medical grounds to pardon Mr. Shaik, his close friend from the liberation struggle and his financial adviser thereafter.

In 2005, a judge ruled that the businessman had made inappropriate payments to the well-connected Mr. Zuma in return for his smoothing the way into various deals, including a lucrative arms contract.

According to the book "The Arms Deal in Your Pocket” by Paul Holden, if government documents prove correct, Mr. Shaik paid Mr. Zuma more than $600,000 over a decade’s time, much of it doled out in modest portions for items like family vacations, medical costs, children’s allowances and even traffic fines.

It seemed that Mr. Shaik "was, in many ways, running Zuma’s financial life and supporting his lifestyle,” Mr. Holden wrote.

Unless it is perhaps more cursed to give than receive, the A.N.C. leader would have to explain this arrangement at trial more satisfactorily than his friend did. The Shaik verdict was confirmed on appeal in 2006.

A Zuma trial would most likely occur next year at the earliest in KwaZulu Natal, far from the seats of government, and if it followed the pace of the Shaik proceedings, it would last about eight months. The president would not be required to attend every day.

"In theory, an accused can say, ‘I am willing to absent myself,’ but that would be unwise,” said Geoff Budlender, one of the nation’s leading lawyers. "You’d want to be present to hear the evidence.”

The case is being pursued by the National Prosecuting Authority, but its leadership is now in limbo. The agency’s director was suspended in late 2007 after discord with Thabo Mbeki, the president at the time.

A commission later concluded that the head prosecutor was a man of "unimpeachable integrity” who ought to be reinstated, but South Africa’s interim president, Kgalema Motlanthe, fired him anyway. The dismissal is being challenged in court.

Mr. Motlanthe, who also is the A.N.C.’s deputy president, seems to realize that naming a new director is kindling for a political firestorm, saying the law should be changed so that the selection comes from a list submitted by an independent body. In the meantime, however, the choice remains either his or, soon, Mr. Zuma’s.

"Whoever becomes director, if they drop the Zuma case, there’d have to be an enormously convincing account of why the prosecution did such a U-turn,” said David Unterhalter, a law professor at the University of the Witwatersrand.

With an election coming, the A.N.C. hired Carl Niehaus as a spokesman late last year. He began a campaign to buff the recent smudges off the party’s image, writing opinion pieces that adoringly described Mr. Zuma as a man deserving of unwavering loyalty.

But the new spokesman turned out to be a bad choice to champion the innocent. Last month, newspaper accounts portrayed him as a man addicted to extravagant living who held off creditors with artful lies.

In one alleged instance, he talked his way into a family holiday at a resort in Mauritius by fibbing about being ill with leukemia to an unwitting travel agent.

"What I did was terrible,” Mr. Niehaus told The Mail and Guardian, a South African newspaper, confessing to forging signatures on checks. He has since quit as a party frontman, leaving the orchestrated praise of Mr. Zuma to others.

The New York Times