Until the military coup of November 1958 the Liberals were one of the main parties representing the southern Sudanese constituencies in parliament.
The Southern Sudanese Political Movement was founded in 1951 by Stanislaus Paysama, Abdel Rahman Sule and Buth Diu.
[8] The party convened a meeting in Juba in October 1954 where the injustices of the Public Service Commission were discussed at length.
The attendees resolved unanimously that the best solution for the south was federation, and called on southerners to prepare to make sacrifices in meeting this goal.
Faced with insistence that the language of Sudan would be Arabic, taught throughout the country, in a 1954 telegram to Harold Macmillan he refused to support a declaration of independence.
In response, the government took steps to weaken the party by saying that no civil servant could engage in politics, and by giving wide publicity to southern chiefs who opposed the conference.
The Liberal Party was among those calling for British military intervention, which some expected to favor the rebels.
In 1957 two intellectuals, Father Saturnino Lohure Hilangi and Ezboni Mondiri Gwanza, founded the Southern Sudan Federal Party (SSFP), which beat the Liberals and won forty seats in the parliamentary elections held in February and March 1958.
[7] After the 1958 elections cynical northerners exploited personal and ethnic hostilities to split the party into rival factions and to win the support of Liberal MPs.
When William Deng, a leader of the exiled Sudan African National Union (SANU) decided to run in the April 1965 elections that followed the handover, Stanislaus Paysama advised him not to form a new party but to revive the Liberal Party, which still had widespread grassroots support.