South Africa’s ruling African National Congress was on the brink of losing its parliamentary majority for the first time Saturday after an election that brought a stunning drop in support for the party that led its country out of apartheid under Nelson Mandela.

Results were not yet final but with more than 97% of votes counted, the ANC had just over 40%. It is a huge slide considering the ANC has dominated South African politics for 30 years since the end of white minority rule in 1994…