The fear gripping senior figures in the ANC is that the party is now so deeply split into Mbeki and Zuma camps that whoever wins will find it difficult to heal the divisions for years to come. This is why even Winnie Mandela's proposal yesterday to cancel the poll itself is being given serious consideration.
But the compromise proposal is flawed. For a start, it does not address the fact that the refusal of both Mbeki and Zuma to step aside from the contest for the sake of the ANC and South Africa itself is at the heart of much of the current strife.
Cyril Ramaphosa, the ANC's former general secretary, summed it up succinctly when he said that the current leadership race was the "wrong race".
Although South Africa under Mbeki has experienced an economic boom, this has not filtered through to the majority of black South Africans who, apart from voting every five years, have seen few changes since the apartheid era. Furthermore, Mbeki's record on liberty, democratic participation and encouraging inclusivity in a divided nation has been disappointingly limited.
Zuma himself is compromised. The country's national prosecuting authority is mulling over when to press charges of alleged corruption, linked to an arms deal. During a trial for rape, of which he was cleared, he suggested he could tell by the way a woman dresses that she was looking for sex, and as a man he was compelled by tradition to oblige.
How has it come to this? Two important political shifts have happened over the past few years that Mbeki appears not to have grasped. ANC members now want both the economic dividend and democratic dividend of South Africa's political miracle.
They want not only the booming economy to deliver to them; they also want the democracy to deliver; democratic watchdogs such as Parliament and the Human Rights Commission to become more accountable, responsive and protective of the vulnerable.
But this also includes the ANC itself and its leaders. There have been increasing calls by ordinary members forit to become more accountable to its members. Yet, this appears to have been lost on Mbeki.
Because of the ANC's archaic internal rules, the rank-and-file have been given the limited choice of Mbeki or Zuma. Younger, more dynamic candidates, such as Tokyo Sexwale, were discouraged from campaigning, or labelled opportunist and careerists.
After his sacking by Mbeki for corruption in 2005, Zuma has become a lightning rod for the grievances of poor South Africans, especially since he has publicly criticised the government's shortcomings. At the same time, Mbeki does not appear to see that the rising wave of support for Zuma is an indication of grassroots disapproval of his continual denial of the consequences of the HIV/Aids pandemic, the explosion of crime and continuing poverty, unemployment and inequality.
Astonishingly, Mbeki appears still not to be able to acknowledge that his oversensitivity to criticism have brought about most of his current difficulties. Or indeed that what South Africa now needs is a leader for a new era, with a greater tolerance for inclusivity.
But there is perhaps still a silver lining in all of this. Depressing, as it may be, this is the ANC's first democratic election for a party leader since the 1950s. And if Zuma wins, it will most probably mean that a new group of people may get a chance to govern. And such are the forces unleashed by this campaign, that even if Zuma wins, he may find himself under greater public scrutiny and an impatient population expecting faster delivery.
The US/UK edition of William Gumede's book Thabo Mbeki and the Battle for the Soul of the ANC, published by Zed Books, is out now