The South African economy [in the 1960s] had already reached an advanced stage of industrialization that had gone beyond simple import-substitution and was beginning export-led growth. Despite this advanced industrial phase, however, the South African economy occupied a similar role in international trade to that of a colony, characterized by the export of raw materials, principally minerals, in exchange for manufactured goods. But this economic relationship was threatened by South Africa's political isolation, which placed markets out of reach, for the sale of raw materials as well as for the purchase of manufactured goods. Furthermore, as a result of a deliberate policy of segregation, the non-white population could not meet the needs of the South African economy. In this way, and in detrimental terms to the South African economy, apartheid became a constraint on domestic demand. For these reasons, and combined with negative world economic conditions, the South African economy had to search for markets elsewhere. Eventually, other pariah states formed trading partnerships with South Africa. But it was the Southern African region that presented the best opportunities to satisfy the requirements of the South African economy. Therefore, for diplomatic and strategic needs as well as for economic reasons, Southern Africa became a priority in South Africa's external policies. South Africa invested heavily in tying that region to its own economy. Co-operation with the Portuguese colonial regime in regional development led to the establishment of substantial stakes in the hydroelectric project on the Cunene river in Angola, and in the huge Cabora Bassa dam in Mozambique. The traditional flow of labour from Mozambique and other countries in the region for mineral extraction and other labour intensive work further reinforced South Africa's role as the economic motor of Southern Africa. In this way, a structure of economic dependence was established.

— The origins of the Angolan civil war by Fernando Andresen Guimarães