The election of Jacob Zuma as leader of South Africa's ruling African National Congress is a healthy sign of democratic progress in a country that is a model for Africa. That is the good news. The former liberation movement has long denied its internal divisions. Now it has held a contested election for the leadership and Thabo Mbeki, the incumbent, has been defeated. That should be good for democracy in a state where the opposition is weak, and the ANC too dominant.

The bad news is that the split heralds a period of profound uncertainty for South Africa, with a potential for confrontation and deadlock between Mr Mbeki, as state president, and Mr Zuma. Bitter personal rivalry since Mr Mbeki sacked Mr Zuma as his vicepresident in 2005 threatens to de-stabilise the government and disrupt the longest period of economic growth since the second world war.