Spanish Civil War, 1936-1939
While Spain's 1901 defeat to Japan may have been a shock(the first defeat of a European country by a non-Western nation), it's more realistic to see the war as one more fall in the country's long, slow decline from its 17th century peak. Spain was shorn of its Pacific possessions, Guam and the Philippines, to go along with the loss of Cuba in a fire sale to the CSA in 1877, and the independence of South America a few generations before that Socialism gained a foothold in the face of a weak monarch and an overbearing aristocracy and Church, but anarchism also gained converts, especially in Catalonia. Repeated rebellions erupted in Morocco, one of its few remaining colonies and one such uprising in 1910 resulted in the death of Miguel Primo de Rivera, a charismatic general of great potential. Spain slowly withdrew into its shell, and did not join either side in the Great War, instead acting as a third-party in prisoner exchanges and the like.
The defeat of the Spanish Army of Africa in the Battle of Annual, to a band of Rif tribal warriors, finally spurred that sleeping giant into action. A military uprising began in 1925, aimed at overthrowing the civilian government and replacing it with a military dictatorship under King Alfonso XIII. But obstacles arose almost immediately. Without a single figure to lead it, the members of the would-be junta squabbled amongst themselves and jockeyed fro power they hadn't yet seized. Many unions members in the socialist UGT and especially the anarchist CNT showed a willingness to fight that few in the army had expected. And with success in doubt, many influential figures, including General Francisco Franco and the king himself, refused to give it their outright support. When the metropolitan army failed to secure Madrid and the crucial southern port of Cadiz in the face of opposition from the unions, Alfonso condemned the coup and it quickly collapsed.
From this fateful decision, the left wing of Spanish politics, generally republican and anti-clerical, slowly began to draw closely to the throne. The 1931 elections, with Spain in economic chaos like the rest of the world, gave the left-wing coalition won a majority of the Cortes-General, and Alfonso appointed as Prime Minister Niceto Alcala-Zamora of the left monarchists, with socialists and republicans in many cabinet positions.
Spain slowly began to pull itself out of the Collapse, and the left-wing government proved better able to help the working class and head off labor trouble than that of the conservatives. But the Church, the landed aristocrats, and the military all chafed under the socialist yoke along with smaller groups like the Falangists, a far-right party which took the Freedom Party as its model. When the left-wing government was re-elected in 1936, a second, much broader uprising began.
Although the Nationalists, as the conservative rebels came to be called, were able to seize the Balearics, the Canaries, Morocco, and Puerto Rico almost immediately, mainland Spain became a battleground. Madrid and Barcelona proved especially tough nuts to crack, even after the Army of Africa, under Emilio Mola, was transported to Andalusia in a daring airlift. Catalonia became a virtual state unto itself under the labor union CNT, as the anarchists would fight the Nationalists but not ally themselves with the king. General Francisco Franco, who, along with Jose Primo de Rivera and Mola was one of the three heads of the rebellion, died in a plane crash off the coast of Portugal as he was being transported from his post in faraway Puerto Rico. Primo de Rivera, the son of a martyred General, became the de facto Nationalist head of government.
Germany, despite having no strong formal ties with Spain, immediately announced its support of the Kingdom of Spain, as did the United States and most other nations. But Britain and France threw in their lot with the Nationalists, partly for ideologically reasons (although both were monarchies themselves) and partly to stick Germany in the eye. Sharing a long border with Spain, France was easily able to ship arms to the rebels, and the French air force under Roland Garros repeatedly bombed the Carlists and anarchists in Navarre and Catalonia. Germany's support was not only more tepid (it too was wracked by the Collapse and distracted by occupation and strife in Eastern Europe, while the ongoing illness of Kaiser Wilhelm II slowed decision-making in foreign-policy to a crawl), but German men and materiel had travel by sea to a friendly seaport, which became few and far between as the Nationalists took more ground.
Like the Mexican Civil War in North America, the Spanish Civil War became a cause celebre, and thousands of European volunteers fought for both sides, such as the British Wellington Legion and the German Königs Brigade.
Under General Sanjuro, one of the few high-ranking officers to remain loyal to the king, the disparate Monarchists fought a defensive war under the weight of Entente metal. The refusal of the anarchists in Barcelona to join forces badly splintered the anti-Nationalist coalition and may have doomed the monarchist cause to defeat. The Basque country fell in 1937, followed by Navarre in 1938. Alfonso evacuated Madrid in March 1939, and the city fell shortly after. The king abdicated and fled to Italy, and the anarchists were crushed in May. Granada, with its symbolic significance, finally fell in June, and the Nationalist victory was complete.
Millions perished in the war and in the purges that followed. The Spanish Civil War was an unprecedentedly bitter, brutal conflict, waged with all the destructive power that modern military science could muster- a harbinger of what was to come two years later.