John Steenhuisen is chosen to head the Democratic Alliance as it struggles with a race row.Read more
BBC Africa, Johannesburg
The deep fault lines in South Africa's main opposition Demoratic Alliance (DA) have been exposed by the resignation of Herman Mashaba from the party, and as mayor of the country's biggest city Johannesburg.
"I cannot reconcile myself with people who believe that race is not important in their discussion of inequalities," he said, in his resignation statement.
It's a far cry from the day when Mmusi Maimane was elected DA leader amid much fanfare, and was described by its spin doctors as the Barack Obama of South Africa.
For the governing African National Congress (ANC), which is itself trapped in seemingly perpetual internal squabbles, the DA's problems are manna from heaven.
The ANC is weak but the largest opposition party in the country is mutilating itself in a corner, unprovoked.
As for Mr Maimane, he is also fighting for his political life.
Standing side-by-side with Mr Mashaba at Monday's press conference, Mr Maimane held his hand high saying: "You are my hero! You are my hero!"
Mr Maimane's fate will be decided in next year's party leadership congress.
But judging by the speed at which events are unfolding, there is no guarantee that he will still be around then.
South African President Cyril Ramaphosa has announced his cabinet, making substantial changes to ministerial positions. He reappointed Nhlanhla Nene as finance minister, reversing his sacking by the former President Jacob Zuma. The leader the Democratic Alliance, the country's official opposition, welcomes the decision but calls into question the increase in VAT announced in the budget speech, last week. This is what Mmusi Maimane told BBC Newsday. (Picture: Mmusi Maimane, leader of the official opposition, the Democratic Alliance, addresses the South African parliament during a parliamentary debate. Credit: Rodger Bosch/AFP/Getty Images)