P.W. Botha

Date: 6 May, 1990

Former leader of the National Party (NP) and head of state, P.W. Botha, resigned from the party in protest against President F.W. de Klerk's reform proposals. He had resigned as state president on 14 August 1989 in the midst of rising political instability, growing economic problems and diplomatic isolation.

References:

http://www.notablebiographies.com/Be-Br/Botha-P-W.html

http://en.wikipedia.org/wiki/National_Party_(South_Africa)