The Suppression of Communism Act 44 of 1950 (renamed the Internal Security Act in 1976) was legislation of the national government in South Africa, passed on 26 June 1950 (and coming into effect on 17 July) which formally banned the Communist Party of South Africa and proscribed any party or group subscribing to communism.
The Act defined communism as any scheme aimed at achieving change--whether economic, social, political, or industrial--"by the promotion of disturbance or disorder" or any act encouraging "feelings of hostility between the European and the non-European races...calculated to further [disorder]". The government could deem any person to be a communist if it found that person's aims to be aligned with these aims. After a nominal two-week appeal period, the person's status as a communist became an unreviewable matter of fact, and subjected the person to being barred from public participation, restricted in movement, or imprisoned. The Act was frequently used to silence critics of racial segregation and apartheid. Justice Frans Rumpff, presiding in the 1952 trial of African National Congress leaders, observed such "statutory communism" might have "nothing to do with communism as it is commonly known."
Passage of the Act was facilitated by the involvement of communists in the anti-apartheid movement. The Act facilitated the government suppression of organizations such as the ANC and PAC that advocated for black equal rights. The Suppression of Communism Act forced these groups to go underground with their activism. Ironically, because of this act, groups such as Umkhonto we Sizwe, led by Nelson Mandela as a branch of the ANC, did seek financial support from the Communist Party. Most of the Act was repealed in 1982 by the Internal Security Act No 74 and the remainder in 1991.