While Saturday's action by the African National Congress's 86-member national executive committee required a day and a half of deliberations, it was actually the culmination of seven years of discontent between South Africa's most powerful politicians, Mr. Mbeki and Mr. Zuma, the man he fired in 2005 as his deputy. Last December, Mr. Zuma defeated his former boss for the congress's leadership in a vote that showed the party deeply split. With that victory, and with the African National Congress dominant in national elections, Mr. Zuma was in line to become president in 2009 when Mr. Mbeki's second term in office expired.

But many of Mr. Zuma's supporters, openly despising the president, wanted him gone sooner rather than later. A majority of the party hierarchy seemed to resist that view until a week ago when a judge's ruling in a corruption case that has long dogged Mr. Zuma tipped the balance. In that decision, the judge not only set aside the case against Mr. Zuma on procedural grounds, he pointed toward what seemed to be a pattern of vindictive political meddling in the matter by Mr. Mbeki's government.

...

But some of the seeds of Mr. Mbeki's undoing were planted [while he was deputy to Mandela]. Once in power, the party's leaders veered from their leftward leanings and did what some have called "the great U-turn," adopting policies of fiscal austerity that reassured the financial markets but postponed most efforts to aid the downtrodden.