Put simply, the African National Congress (ANC) was responsible for pushing South Africa away from apartheid. The ANC's attitude under Nelson Mandela helped to create a new South Africa after the end of the apartheid regime. This new South Africa is, to some extent, under threat now as the ANC seems to be moving towards one-party rule that is hostile to non-blacks.
When apartheid ended, the actions of Mandela and the ANC helped to keep South Africa stable. They did not engage in the sort of anti-white actions that have caused so much trouble in neighboring Zimbabwe. However, in recent years, the ANC has seemed to be moving toward a less open and democratic system. It seems to be trying to take more power for itself and to demonize as racist any opposition to its rule. This is a worrisome development.