By Martin Plaut
BBC Africa analyst
Thabo Mbeki has been left with few friends in the upper ranks of the ANC
The African National Congress's decision to sack President Thabo Mbeki has been described by some South African commentators as "regicide".
Certainly it is unprecedented in South African history that a head of state is dismissed in this way. Nor is the ANC the kind of organisation that goes in for this humiliation of its leaders.
So why did it happen?
The immediate cause was Mr Mbeki's ongoing feud with his former deputy, the ANC party leader Jacob Zuma.
But this was not just a personal vendetta between two men. Behind these events lie two major factors: one political, one personal.
Fight with the left
Thabo Mbeki, although a former member of the South African Communist Party, has used conventional economic policies to drive the country's development agenda.
Tight monetary and budgetary targets have been set and met. The result has been a period of unprecedented economic growth, reaching 5% a year in recent years.
In June 1996 Finance Minister Trevor Manuel introduced a neo-liberal economic strategy known as Growth, Employment and Redistribution (Gear).
This included commitments to open markets, privatisation and a favourable investment climate.
The ANC is in a formal alliance with two groups on the left, the Communists and the trade union movement, Cosatu. Both were fiercely critical of the strategy and argued that they had been excluded from its development and implementation.
In the report to the Communist Party Congress in July 1998 the Central Committee spelled out their objections to Gear in great detail.
This concluded: "We remain convinced that Gear is the wrong policy. It was wrong in the process that developed it, it is wrong in its overall strategic conception, and it is wrong in much of its detail.
"At the end of the day, we cannot allow our entire transformation struggle to be held hostage by conservative approaches to the budget deficit."
In May this year Blade Nzimande, General Secretary of the Communist Party wrote: "Despite the many modest gains that our own democracy has made since the 1994 democratic breakthrough, our own self-imposed structural adjustment programme, Gear, failed to make a dent in unemployment (unemployment actually increased dramatically between 1996 and 2006), and eroded the capacity to build a developmental state."
These criticisms are not just held by the Communist Party, they are a reflection of the unease on the left as a whole at the policies that Thabo Mbeki adopted.
Anger at the president's strategy to tackle the problems of unemployment, in particular, contributed to his downfall.
All politicians make enemies. That is the nature of the game. But President Mbeki has made more than most. One example should suffice to illustrate the problem.
In April 2001 the country's national daily, the Star, had a headline that read "Mbeki plot rocks ANC".
President Mbeki had sent his minister of safety and security to accuse three leading members of the party of plotting to oust him.
The accused - former ANC secretary-general, Cyril Ramaphosa and two former provincial premiers, Tokyo Sexwale and Mathews Phosa - were among the party's most respected figures.
All three were men who had driven to seek their fortunes in business after being marginalised by Mr Mbeki.
To this day there is no clear explanation of why these extraordinary charges were made. Nelson Mandela himself emerged from retirement to say that he held all three in "high esteem".
The Mail and Guardian newspaper commented at the time that it was a strategy worth of Joseph Stalin and said: "Many observers have dismissed the plot theories as a strategy to warn off potential competitors with ambitions to challenge Mbeki's leadership."
No evidence was ever led against them, no charges were laid and the matter was swept under the carpet. However, it was certainly not forgotten.
Today Mathew Phosa is the ANC Treasurer General, one of the top party posts. Cyril Ramaphosa and Tokyo Sexwale are members of the National Executive.
Their names, along with those of Zwelinzima Vavi, leader of the trade unions in Cosatu and Blade Nzimande of the Communist Party, have been cited in the South African press as among those who wielded the knife against Thabo Mbeki.
The political and the personal had come together.