World War II raged from 1939 to 1945, with Axis powers vying against the Allies. The Axis included Germany, Japan and Italy and their allies; against them were the United Kingdom, the U.S., the Soviet Union, France and their allies. Among the large European nations not directly involved in the conflict was Spain, which had just struggled through a civil war. Spain maintained a policy of military neutrality through World War II due to complicated diplomatic policies heavily influenced by their civil war.

Neutrality versus Non-Belligerency

Antonio Marquina, writing in ''The American University International Law Review,'' distinguishes Spain’s policy of non-belligerency from genuine neutrality, because Spain provided economic and intelligence assistance to the Axis. General Francisco Franco headed Spain’s right-wing military dictatorship; Germany and Italy supported Franco’s side in the Spanish Civil War, and he remained sympathetic to them and their leaders, Adolf Hitler and Benito Mussolini. Franco signed the Protocol of Hendaya in 1940, which provided for close cooperation among the three governments.

Strategic Pressures

Early in the war, the Axis pressured Spain to seize control of strategically pivotal Gibraltar, a British holding since 1704. German advances in Egypt closed the Mediterranean Sea to the Allies in the east, and control of Gibraltar would close it from the west as well, cutting off British forces in North Africa. Franco delayed committing Spain to open warfare; he insisted Germany supply Spain with grain before he would agree to the assault on Gibraltar. By the summer of 1941, Germany had switched its focus from the south and west to the north and east, invading the Soviet Union, and pressure on Gibraltar eased.

Economic Pressures

As Axis negotiators worked to force Spain’s hand, Allied diplomats strove just as hard to keep Spain out of the war. Among their chief tools were economic incentives. In a combination of humanitarian support and strategic blockade, Portugal provided grain to ease a famine in Spain, while British and American oil companies reduced Spain’s access to petroleum. The Allies enacted trade sanctions that severely circumscribed Spanish exports while limiting Spanish imports of important products, including fertilizer. Under serious economic pressures after its civil war, Spain could not afford to further jeopardize its economy or food supply.

Political Pressures

Allied negotiators supported Franco’s political opponents, particularly the military leaders of the civil war; these men, according to Marquina’s analysis, represented a homegrown alternative to the Falange, the Franco-centric party supported by Germany and Italy. In 2013, the British government released previously secret documents revealing that British intelligence spent the equivalent of more than $200 million in bribes to such military leaders and other influential men, at the behest of MI6 agents and ambassador Sir Samuel Hoare. More public were the pressures brought by government figures like General Francisco Gómez-Jordana y Sousa, who became Foreign Minister in 1942; historian Stanley G. Payne calls him a “covert neutralist.” By the following year, the change in Axis military prospects and the pressures of covert and public diplomacy motivated Franco to reduce his support of the Axis and adopt a more genuine neutrality policy.