This led to great disillusionment amongst South Africa's white liberal community, and some questioned the merit of continuing to serve in the apartheid parliament.

President F. W. de Klerk released Nelson Mandela and announced the unbanning of struggle organisations such as the African National Congress, while embracing liberal democracy and opening up its membership to all races.

By 1998, the party was growing its support base significantly, and after the 1999 election, the DP, under the leadership of Leon, became Official Opposition to the ANC-led government, winning 38 seats.

In the Western Cape province, it achieved kingmaker status and became the junior partner in a governing coalition with the renamed New National Party (NNP).

The merger agreement was short-lived, with the NNP leaving the alliance in 2001, but the DA closed ranks and retained the new creation, establishing it at all levels of government from 2003 onwards.