In her Business Day column this week Karima Brown wrote that Jacob Zuma "will either be the next president of SA or will endorse Motlanthe as his successor." The underlying assumption being that - as night follows day - the ANC will win the next election. This expectation, shared as it is by everyone, would ordinarily have been worthy of no comment at all. Since 1994 South Africa has lived under one-party dominant rule. The ANC has monopolised the loyalties of the black population. Its support has only crept upwards from its 62% in 1994, to 70% in 2004, to 75% in 2005. There has never been any foreseeable prospect of it actually losing an election at national level.

Yet, for some reason, Brown's statement came across as slightly incongruous. In December the ANC went and decapitated itself. Corruption has been rotting away the party's moral authority and ability to govern effectively. The catastrophic power outages of last week have now done to the ANC government what Black Wednesday (1992) did to the Tories: shattered their reputation for competent handling of the economy.

So far the new ANC leadership has offered nothing but ‘more of the same, but worse.' The belief that the ANC "will be in power forever" seems to underlie many of their actions. The efforts to repair party unity have been desultory. There is no sign of any willingness to act against corruption or pull back from the policy of Africanisation-at-whatever-the-cost ('transformation'). Indeed, its justificatory rhetoric has already become tinged with anti-white racism. Much of the leadership is deeply implicated in the wrongdoing of the Mbeki-era. Jeff Radebe, for one, was the minister directly responsible for holding Eskom back from building new generating capacity.

(The one grouping within the party which has a sense of what is going wrong, and what needs to be done to correct it, are the ANC ‘technocrats' - most notably Finance Minister Trevor Manuel. But almost all these individuals were ejected from the leadership at or after Polokwane.)

The question is: for how long can the ANC go on flouting the usual rules of democratic politics before its popular support gives?

Even though there is no sign of this on the horizon, this does not mean that change couldn't come soon. The ANC is not the first ruling party to enjoy such dominance. And the experience of others teaches that change in such a system has three qualities: It is unexpected, dramatic, and (usually) irreversible. The example of the National Party in South Africa, ZANU-PF in Zimbabwe, and the Indian National Congress (INC) in India all illustrate this point.

Following independence from Great Britain in 1947 Congress dominated Indian politics. In the constituency-based elections to the Lok Sabha - the lower house of the Indian parliament - the INC won 74,4% of seats in 1952, 75,1% in 1957, and 73,1% in 1962.

However, in the first edition of The Government and Politics of India (1964), W.H. Morris-Jones noted that the image of the INC was "becoming daily more tarnished." He asked, "how can the people see Congressmen as other than office-seekers without scruple and office-holders without merit? How long can the party live on its capital?"

The answer to that question came three years later. In the national elections in 1967 the INC was returned to power, but with only 54,9% of the seats. This set-back dissipated Congress's aura of immortality, even though it was able to hang on to power for another two terms

In Zimbabwe too ZANU-PF was in an utterly dominant electoral position through the 1980s and 1990s. In 1995 it won 118 out of 120 seats in the parliamentary elections. In the presidential elections the following year Robert Mugabe was returned to office with 92,8% of the popular vote.

That immense majority crumbled in the space of months from late 1999. In February 2000 the government was defeated in a constitutional referendum. And ZANU-PF and Mugabe would have been resoundingly defeated in the parliamentary elections that year - and the presidential poll in 2002 - had they not tyrannised the country and then rigged the results.

In South Africa the National Party dominated white politics from 1948 through to the mid-1990s. A Markdata poll conducted in May 1994 found that the NP had the support of 16,3% of the population, the Democratic Party 0,5%, and the Freedom Front 3%. Among those white South Africans polled the NP had the support of 61,3%, the Freedom Front 10%, and the Democratic Party 5%.

The NP sustained this basic level of support up until early 1998. A poll conducted by Markdata in February that year estimated its support at 15,1%, the DP's support at 4,2%, and the FF's at 3%. Yet, within the next few months the NP's support among white South Africans collapsed. A June 1998 poll found that the DP and NP were level pegging at around 10% of the vote. The NP's support was sustained only by its continuing support among Coloured voters. The NP collapsed to 6,9% of the vote in 1999 and then 1.7% in 2004, before disappearing completely.

In all these cases no one saw these shifts coming until they had happened. Of course afterwards, they were described as 'inevitable'.

At some point the ANC's hold upon its support is going to break. It is just a matter of when. It could be in a month, a year, or a decade. Still, the new leadership's efforts to dissolve the Directorate of Special Operations have shown them to be office-seekers ‘without scruple.' And, the power-outages (et al) of last week have revealed the ANC in government to be office-holders ‘without merit.' How long then can our dominant party carrying on living off its capital? Cosatu and the SACP may yet come to regret their victory at Polokwane. If they had lost and been forced to form a break away party, they could have campaigned on a promise of change and a renewal. As it is they have taken over ship that, once it starts taking on water, is going to sink very quickly.