Whichever way Judge Herbert Msimang rules, to either adjourn or abandon the case against Jacob Zuma, the ensuing drama will change the very nature of the ANC and the political landscape of South Africa.

If the case goes ahead, it is clear from papers already submitted to court by the defence that Zuma is going to go on the attack, trying to fight fire with fire with accusations that President Thabo Mbeki was not only engaged in a sinister political conspiracy to destroy his own deputy, but was himself involved in the arms deal negotiations with which Zuma is now charged.

This is explosive stuff. Zuma has already breached ANC protocol by launching political attacks on the president and his policies from public platforms. If he compounds that with more personal attacks on the president in a court of law, it will amount to open warfare between the two most powerful politicians in the country. This could plunge the ANC and the country into an unprecedented political crisis.

If, on the other hand, Judge Msimang upholds the defence application and orders the charges against Zuma to be permanently withdrawn, the country might find itself in the extraordinary situation of having a candidate for the presidency who was charged with corruption, but never tried for it - and therefore never cleared of it.

South Africa could find itself with a president, a national figurehead, living under the cloud of a High Court judge's finding that he had been party to "a generally corrupt relationship" with a convicted fraudster. Zuma once cried out to have his "day in court" to remove that cloud, to publicly establish his innocence. Yet now he is fighting to avoid it.

Of course, not everything about Zuma's challenge to Mbeki is negative. There is an upside. It has revived the ANC's tradition of robust internal debate that some critics felt Mbeki was stifling with his centralised style of leadership and low tolerance of criticism.

It has highlighted the difference between the ANC and the stereotype of so many ruling parties in Africa, where sycophantic subservience is the norm, where the press is mute and even the most tyrannical and incompetent leaders are left to rule for life. Not for us the passivity of the Zimbabweans who lie prostrate under the heel of Robert Mugabe.

Mbeki is neither incompetent nor tyrannical. He has presided over an economic miracle to follow Nelson Mandela's political miracle, turning a deathbed economy inherited from the apartheid regime into a prosperous one that has just completed 30 consecutive quarters of sustained growth for the first time in the country's history; that has boosted social grants to a massive R70 billion a year which reach 10 million of our poorest people; and that earlier this year was rated by City Bank of New York as one of the three most exciting emerging economies in the world.

Yet Mbeki is being assailed for his failures, on Aids and Zimbabwe and for not narrowing the wealth gap or reducing unemployment sufficiently, in a way that has not happened in any other African country - and many I can think of in the developed world.

This is healthy. If the Zuma camp's criticisms of Mbeki's personal remoteness and centralised style of governance can serve as a corrective both within this administration and those that will come after it, the country will be well served.

But there could be a tipping point somewhere ahead if this trial proceeds in the manner that the court papers portend. If the open warfare between the country's two most powerful figures becomes too vicious, it could poison relations between their respective camps to an irreconcilable degree.

That could paralyse both the ruling party and the administration of the country - for there is no viable opposition waiting in the wings as an alternative government ready to take over. That may come in time, but it is not there yet. So for the moment, the national condition is bound up with that of the ANC.

Mbeki has already warned that the Zuma crisis is so preoccupying members of the ruling party across the country that delivery on important government programmes is suffering. That could get a whole lot worse.

It could also create a leadership vacuum and a succession crisis. With a ruling party divided into two embittered camps, how does one choose a new leader? Whoever is chosen from either camp will be unacceptable to the other.

The only way, and it may yet come to this before the ANC's all-important national conference late next year, would seem to be for the core members of the party, its elders and long-standing custodians of its traditions, to dig deep and come up with a candidate whom they believe can be acceptable to both sides and who has the credentials and personality to begin a process of healing and reuniting.

It may not be the most democratic of processes, but democracy, too, has its vulnerable moments when it is infected by a spirit of populist hedonism - or how to get closer to the cookie jar - of the kind that is infecting our society now in what is still a complex transition, not only from apartheid to democracy, but also from economic exploitation to greater opportunities for the previously disadvantaged sectors of the community.

We need a stabilising hand to steady the ship.

It is all too easy, in a post-revolutionary cycle which has repeated itself throughout history, for more radical elements to accuse the initial victors of betraying the revolution because they have failed to deliver a Nirvana of equal prosperity for all in a few short years.

It usually leads to a chain-reaction of intra-revolutionary revolutions: from the Girondins to the Montagnards to Robespierre and the guillotine; and from the Mensheviks to the Bolsheviks to Stalin and the terror, before it finally produces a Thermidorian reaction - from Khrushchev to Gorbachev, and a gradual return to normality. But by then many people have died and economies have collapsed and rebuilding is a long, hard haul.

I am not suggesting we are on that disastrous cycle, but at least let us recognise the symptoms and take remedial action before it gathers momentum and destroys much of what we have achieved. Ours has been a truly remarkable, if not entirely perfect, transition from apartheid authoritarianism to a pretty decent democracy, and from crude group exploitation to affirmative action, black economic empowerment and significantly improved welfare payments.

I would feel a whole lot easier about the Zuma camp if it were to tell us more precisely what policies it would implement to bring about a much faster expansion of our economy than the Mandela and Mbeki administrations have achieved; how it would create many more long-term jobs in a short space of time with our poorly skilled labour force in this cruelly competitive globalised environment - and not leave me and many like me with the strong impression that its fight is just a personality scrap and a desire to get its man closer to the national levers of power for its own collective benefit.

Sparks is a veteran journalist and political commentator.

With acknowledgement to Allister Sparks and Cape Times.