Over the course of the 1960s, Portugal, Rhodesia, and South Africa, hard-pressed by African nationalist movements and international opinion, grew closer together, realising that their common enemies could only be defeated by a common stance. The most important attempt to meet the threat to white political domination in Southern Africa was Exercise ALCORA, a military understanding negotiated, in secret, in October 1970. From then until the Portuguese Revolution in 1974, regular meetings of the representatives of the three countries’ armed forces pooled intelligence and defined new strategies for the on-going conflicts in Rhodesia, Angola, and Mozambique, and put in train plans for future, larger-scale clashes. This article examines the origins of ALCORA, charting the process by which Lisbon, Salisbury, and Pretoria came together despite considerable obstacles. It highlights the importance of domestic factors, notably in South Africa, ALCORA’s senior partner. There, the murder in 1966 of Prime Minister Hendrik Verwoerd led to a circumstance wherein leading figures of the regime enjoyed much greater freedom in the definition of policy than before. One beneficiary was Defence Minister P. W. Botha who, with the army’s backing, would develop a total strategy against what was perceived as a total threat. Exercise ALCORA was a key component of this strategy.