Under its leader John X. Merriman, the South African Party governed Cape Colony in a unity government with Afrikaner Bond from 1908 until the formation of the Union of South Africa in 1910.
During the National Convention on Union, Merriman and other South African Party representatives fought to extend the Cape's multi-racial franchise system (whereby minor property and literacy suffrage qualifications applied equally to all male citizens, regardless of race) to the rest of South Africa, post-union.