In the 1920s, following the Battle of Anoual, France provided military support to Spain to help secure its occupation of the Rif. Four decades later, General De Gaulle extended technical and scientific assistance to Franco for Spain's atomic bomb project, with plans for the detonation to take place in Western Sahara. After Morocco regained Tan-Tan and Tarfaya in 1958, Franco's Spain grew increasingly concerned that this wave of independence could eventually force it to relinquish Western Sahara, a territory it had occupied since 1884. To counter this threat, Franco sought support from another military leader-turned-politician: Charles de Gaulle, who had recently come to power in France. Both leaders shared a common distrust of Morocco's ambitions to restore its Cherifian Empire. This was evident in France's role in facilitating Mauritania's independence on November 28, 1960—a move that Morocco refused to recognize until 1969. According to Francisco Gómez Balcázar in The Secret of the Spanish Atomic Bomb, this Franco-French alliance extended beyond politics. In the early 1960s, De Gaulle and Franco struck a deal allowing Spain to develop nuclear weapons, including setting up a reactor outside the control of the International Atomic Energy Agency (IAEA) and the U.S. nuclear watchdog. This cooperation, which angered the United States, transformed Spain's nuclear ambitions from a fringe scientific initiative—started by a group of Spanish researchers in 1948—into a state-controlled project. Luck also played in Spain's favor. In 1966, an American military plane crashed into the waters off Galicia, carrying two nuclear bombs. Spanish authorities managed to seize one of them, gaining crucial insights into nuclear technology. As Balcázar notes, «This crash was a catalyst for Spain's nuclear energy officials, reigniting their program». The Loss of Sidi Ifni Accelerates Spain's Nuclear Plans By 1969, Franco faced growing pressure from Morocco's southern liberation army and was ultimately forced to cede Sidi Ifni. This loss only reinforced Spain's determination to develop an atomic bomb, which Franco planned to test in Western Sahara in the early 1970s—mirroring De Gaulle's earlier decision to conduct France's first nuclear test in the French-occupied eastern Sahara. However, Spain's nuclear ambitions never materialized. King Hassan II had made reclaiming Western Sahara a cornerstone of his reign, especially after surviving two coup attempts in 1971 and 1972. In the lead-up to the Green March on November 6, 1975, he mounted a strong international diplomatic campaign, even securing an advisory opinion from the International Court of Justice to support Morocco's claim over the territory. Franco's death further sealed the fate of Spain's nuclear program. His successor, King Juan Carlos, had no interest in waging war against Morocco to maintain Spain's hold on the Sahara. Instead, he focused on reconciling the Spanish people with the monarchy after decades of division under Franco. Spain's nuclear ambitions officially came to an end when the Socialist Party took power in 1981. In 1987, Prime Minister Felipe González's government ratified the Treaty on the Non-Proliferation of Nuclear Weapons, closing the chapter on Spain's nuclear aspirations for good.
