Crisis Phase (December 17, 1965-May 9, 1973): On December 17, 1965, the United Nations General Assembly approved a resolution requesting Spain to decolonize the territory. On December 20, 1966, the UN General Assembly approved a resolution requesting Spain to organize, under UN supervision, a referendum on self-determination of the territory. Saharawi nationalists led by El-Ouali Mustapha Sayed established the Frente Popular para la Liberation de Saguia el-Hamra y Rio de Oro (Polisario Front) in the Spanish Sahara on April 29, 1973. The UN General Assembly approved a resolution on December 13, 1972, which called for the independence of Spanish Sahara and urged Spain to hold a referendum in the territory to decide its future status.
Conflict Phase (May 10, 1973-February 26, 1976): Polisario’s armed wing, the Saharawi People’s Liberation Army (SPLA), began a rebellion against the Spanish colonial government on May 10, 1973. Libya provided military assistance in support of the Polisario. Spain proposed a referendum on the status of the Spanish Sahara (Western Sahara) on August 21, 1974, but the proposal was eventually abandoned. Morocco and Mauritania claimed sovereignty over the territory. The UNGA approved a resolution urging the International Court of Justice (ICJ) issue an advisory opinion on the status of the territory on December 13, 1974, and the matter was referred to the ICJ on December 21, 1974. The UN secretary-general sent a fact-finding mission to the territory from May 8 to June 9, 1975. On October 15, 1975, the UN fact-finding mission reported that a majority of the inhabitants of the territory favored independence. The ICJ issued a ruling on October 16, 1975, which suggested that while there were historical ties between the territory and both Morocco and Mauritania, these ties were not sufficient to preclude the people of the territory choosing to establish an independent country. King Hassan of Morocco initiated the Green March of some 350,000 Moroccans across the border of Western Sahara on November 6, 1975. Spain agreed to abandon the territory to Morocco and Mauritania on November 8, 1975, and King Hassan of Morocco ordered the marchers back into Morocco on November 9, 1975. Spain, Morocco, and Mauritania signed the Tripartite Agreement on November 11, 1975, in which Spain agreed to relinquish administrative control of the territory (but not sovereignty) to Morocco and Mauritania. Algeria provided military assistance in support of the Polisario. Algerian troops intervened in support of Polisario in January 1976, resulting in the death of 30 Algerian soldiers. Spain withdrew its troops from Spanish Sahara on January 12, 1976, and Spain’s presence in the territory formally ended on February 26, 1976. Morocco immediately claimed sovereignty over the territory. Some 5,000 individuals were killed during the conflict.
[Sources: Allock et al., 1992, 294-308; Brogan, 1992, 53-61; Tillema, 1991, 138-140; Weisburd, 1997, 244-247.]