The investigation into Mr Cyril Ramaphosa, Mr Tokyo Sexwale and Mr Matthews Phosa for allegedly plotting to overthrow and harm President Thabo Mbeki marks a major split in the African National Congress (ANC).
It underscores developing divisions within the organisation since it took power upon the election of Mr Nelson Mandela as president seven years ago this month.
While the Safety and Security Minister, Mr Steve Tshwete, refused to give full details of the allegations against the three men, in a dramatic television appearance he hinted that Mr Mbeki was in physical danger. Because of the conspiracy, Mr Tshwete said, the president's personal security had been strengthened.
Few analysts believe that the three men accused of conspiracy would resort to violence. Each one is a prominent member of the South African business community and it is thought more likely that they may be using their wealth in a campaign to replace Mr Mbeki democratically and constitutionally when his term comes to an end.
In a variation of the old slogan "one-man, one vote", some ANC members dismayed at Mr Mbeki's record on AIDS have been using the slogan "one president, one term" in discussions within the party.
Mr Mbeki has lost a great deal of popularity and credibility inside and outside the ANC with his publicly stated views that HIV may not lead to AIDS.
There are believed to be 4.7 million HIV positive people in South Africa, higher than in any other country. Up to 250,000 deaths from AIDS occur each year and the health crisis is the most serious political and social problem in the country.
While Mr Tshwete may yet be borne out in his claim that the police investigation will produce evidence which is extremely damaging to the three men, there is serious concern that the "conspiracy" and the subsequent police investigation may have been invented in order to bolster Mr Mbeki's chances of retaining power.
Either the three "conspirators" are genuinely suspected of serious wrongdoings or the South African police is being used as a political weapon to sort out differences within the ANC. Either way the development conveys a disturbing message for South Africa's hard-won democracy after nearly half a century of rule by the old Afrikaner-dominated National Party.
Mr Ramaphosa, a member of the minority Venda nationality from the north of the country, was favoured by Mr Mandela as his successor but in the race to become deputy president he lost to Mr Mbeki, who had the support of the ANC's Youth League and Ms Winnie Mandela.
It is significant that the only serious allegations against the three men to be disclosed by Mr Tshwete were those of holding secret meetings and voicing accusations that Mr Mbeki was involved in the murder in 1993 of South African Communist Party (SACP) leader Mr Chris Hani.
Mr Hani was a particularly charismatic politician and despite the SACP's minority role within the ANC's campaign might have been regarded as an eventual candidate for the presidency of a democratic South Africa and therefore a challenge to Mr Mbeki.
The inclusion of this allegation underscores the fact that challenges to the presidency are at the heart of the current crisis.
There have been rumours for some time that Mr Ramaphosa may wish to make a political comeback at the end of the current presidential administration in 2004.
He is immensely popular within the ANC in which he is a member of the 60-strong executive.
His success as a black businessman has also provided him with the wealth to mount a strong challenge to the current leadership.
He is chairman of the publishing group Johnnic, which has an interest in the daily newspaper Business Day and executive chairman of Rebserve, a management services company.
Mr Sexwale is a former premier of Gauteng, South Africa's most populous region which includes Johannesburg and Pretoria, and was once an officer in the Soviet armed forces during his exile from South Africa in the apartheid era.
He is chairman of the energy group Mvelaphanda holdings and deputy chairman of the diamond producers Transhex.
After being involved in drafting South Africa's constitution, Mr Ramaphosa made his decision to move from mainstream politics in 1996, while Mr Sexwale and Mr Phosa both opted for business over politics the following year.
