The Portuguese, who had settled in Africa and ruled considerable territory since the 15th century, believed in a multi-racial overseas empire. Portuguese leaders, including Salazar, defended the policy of multiracialism and civilising mission, or Lusotropicalism, as a way of integrating Portuguese colonies, and their peoples, more closely with Portugal itself. For the Portuguese ruling regime, the overseas empire was a matter of national interest. The Portuguese having been in Africa for much longer than the other colonial empires had developed strong relations with the local people and therefore was able to win them over. In Portuguese Africa, trained Portuguese black Africans were allowed to occupy positions in several occupations including specialized military, administration, teaching, health and other posts in the civil service and private businesses, as long as they had the right technical and human qualities. In addition, intermarriage with white Portuguese was a common practice since the earlier contacts with the Europeans. The access to basic, secondary and technical education was being expanded and its availability was being increasingly opened to both the indigenous and European Portuguese of the territories. Examples of this policy include several black Portuguese Africans who would become prominent individuals during the war or in the post-independence, and who had studied during the Portuguese rule of the territories in local schools or even in Portuguese schools and universities in the mainland (the metropole) – Samora Machel, Mario Pinto de Andrade, Marcelino dos Santos, Eduardo Mondlane, Agostinho Neto, Amilcar Cabral, Jonas Savimbi, Joaquim Chissano, and Graca Machel are just a few examples. Two large state-run universities were founded in Portuguese Africa in the 1960s (the Universidade de Luanda in Angola and the Universidade de Lourenco Marques in Mozambique, awarding a wide range of degrees from engineering to medicine), during a time that in the European mainland only four public universities were in operation, two of them in Lisbon. Several figures in Portuguese society, including one of the most idolized sports stars in Portuguese football history, a black football player from Portuguese East Africa named Eusebio, were other examples of multiracialism.
The conflict began in Angola on 4 February 1961. In March 1961, the US backed UPA (Angola People Union) which was based in Zaire entered northern Angola and proceeded to massacre the civilian population killing about 1,500 whites and 20,000 blacks (women and children included of both white European and black African descent) through cross-border attacks, under the full knowledge of the US Government – it was the start of the Portuguese Colonial War. John F. Kennedy would later notify Antonio de Oliveira Salazar (via the US consulate in Portugal) to immediately abandon the colonies. A US backed coup which would be known as the Abrilada, was also attempted to overthrow Salazar’s Estado Novo regime. It is due to this failed coup that Salazar was able to consolidate power and finally send a military response to the massacres occurring in Angola. As the war progressed, Portugal rapidly increased its mobilized forces. In addition, by the end of the Portuguese colonial war, in 1974, black African participation had become crucial, representing about half of all operational colonial troops of Portugal. By the early 1970s, the war was already won. The military threat was so minor at the later stages that immigration to Angola and Mozambique was actually increasing, as were the economies of the then Portuguese territories.
In early 1974, the war was reduced to sporadic independentist guerrilla operations against the Portuguese in non-urbanized countryside areas far away from the main centers. The Portuguese have secured all cities, towns and villages in Angola and Mozambique, protecting its white, black and mixed race populations from any sort of armed threat. A sound environment of security and normality was the norm in almost all Portuguese Africa. The only exception was Portuguese Guinea, the smallest of all continental African territories under Portuguese rule, where independentist guerrilla operations, strongly supported by neighbouring allies like Guinea and Senegal, managed to have higher levels of success. The guerrilla war was almost won in Angola, shifting to near total war in Guinea (although the territory was still under total control of the Portuguese military), and worsening in the north of Mozambique. The US was so certain that the Portuguese presence in Africa was guaranteed that it was completely caught by surprise by the effects of the Carnation revolution.
The Soviet Union, realising that a military solution it had so successfully employed in several other countries around the world was not bearing fruit, dramatically changed strategy. It focused instead on Portugal. With the growing popular discontent over the casualties of the war and due to the large economic divide between the rich and poor the communists were able to manipulate junior officers of the military. A group of Portuguese military officers under the influence of communists, would proceed to over throw the Portuguese government with what was later called the Carnation Revolution on 25 April 1974 in Lisbon, Portugal. This led to a period of economic collapse and political instability.