Background

The Spanish Civil War emerged from the sustained political-social crisis of the Second Spanish Republic (1931–1939). The Republic had been proclaimed on 14 April 1931 after the collapse of the Bourbon monarchy under King Alfonso XIII, who had abdicated and gone into exile following the defeat of the monarchist parties in the April 1931 municipal elections. The Republic attempted a substantial program of political-social reform — land redistribution, secularization, regional autonomy for Catalonia and the Basque Country, the abolition of various traditional privileges — that progressively polarized Spanish politics through the 1930s.

The political polarization produced two electoral cycles in opposite directions: the centre-left coalition of 1931–1933, the centre-right coalition of 1933–1936 (during which substantial portions of the earlier reforms were reversed), and the Popular Front left coalition that won the February 1936 elections. The Popular Front government’s first months in office produced substantial political violence on both the radical left and the radical right, including approximately 350 political assassinations between February and July 1936.

The military rising

A coordinated military rising against the Popular Front government began on the evening of 17 July 1936 in Spanish Morocco and spread to peninsular Spain on 18 July. The conspiracy involved senior generals (Mola, Sanjurjo, Goded, Queipo de Llano, and — joining later — Franco) and the Falange (the Spanish fascist movement) and Carlist (traditionalist monarchist) civilian organizations. The plan envisioned a rapid coup; the Republican government was supposed to collapse within days.

The coup partially succeeded. Approximately one-third of the Spanish military mainland forces joined the rising; another third remained loyal to the Republic; the remainder split. The Nationalists secured approximately one-third of Spain’s territory in the first week — including most of the conservative Catholic agrarian regions of the north and northwest. The Republicans retained Madrid, Barcelona, Valencia, Bilbao, the Basque Country, Catalonia, and most of the urban-industrial regions of the south and east. The country was divided. The war began.

Foreign intervention

Both sides immediately sought foreign military support. The Nationalist appeals to Nazi Germany and Fascist Italy produced substantial military intervention beginning in late July 1936:

  • German intervention: the Condor Legion (approximately 19,000 personnel over the war), including the bomber squadrons that conducted the bombing of Guernica (26 April 1937), the Heinkel He-51 and Messerschmitt Bf 109 fighter squadrons, and substantial armoured and signals support. The Condor Legion provided the German military with substantial pre-WWII combat experience.
  • Italian intervention: approximately 80,000 personnel of the Corpo Truppe Volontarie plus substantial aviation and naval forces. Italy’s contribution was numerically larger than Germany’s but militarily less effective.
  • Portuguese support: approximately 20,000 Viriato volunteers and substantial logistical support.

The Republican government’s appeals to the Western democracies (Britain, France, the United States) produced the Non-Intervention Pact of August 1936 — a notional multilateral agreement that no foreign country would intervene, which was substantively respected by the Western powers and substantively violated by Germany, Italy, and Portugal. The Republic’s effective foreign support came from:

  • The Soviet Union under Stalin, which provided substantial military equipment (tanks, aircraft, military advisers) in exchange for the substantial Spanish gold reserves (transferred to Moscow in 1936 and never returned).
  • The International Brigades: approximately 32,000 foreign volunteers from approximately 50 countries who fought on the Republican side, organized through the Communist International. The Brigades included substantial American, British, French, German exile, Italian exile, and Polish contingents. Notable foreign participants included George Orwell (whose Homage to Catalonia is the major English-language memoir of the war) and Ernest Hemingway (whose For Whom the Bell Tolls is the major novel).

The war

The war was fought in three substantial phases. Phase one (July 1936 – March 1937): Nationalist failure to take Madrid in the Battle of Madrid (November 1936 – February 1937), the early Republican defensive consolidation, and Italian failure at the Battle of Guadalajara (March 1937). Phase two (April 1937 – April 1938): Franco’s systematic destruction of the northern Republican zone (the Basque Country, Asturias, Cantabria), including the bombing of Guernica by the Condor Legion and the eventual capture of Bilbao (June 1937), Santander (August), and Gijón (October). Phase three (April 1938 – April 1939): the Nationalist offensive across Aragon to the Mediterranean (April 1938), which split the Republican zone in two; the Battle of the Ebro (July–November 1938), the longest and bloodiest battle of the war; and the final Nationalist offensive in Catalonia (December 1938 – February 1939) that took Barcelona on 26 January 1939. Madrid surrendered on 28 March 1939. Franco declared victory on 1 April.

The war’s atrocities were substantial on both sides. The Nationalist Causa General (the postwar national investigation into Republican violence) documented approximately 50,000 killings by Republican-aligned forces in Republican-controlled territory. Modern historiography places Nationalist political killings in Nationalist-controlled territory at approximately 200,000 during the war and an additional 20,000–50,000 in the postwar repression of 1939–1945. The wartime aerial bombing of cities — Madrid, Barcelona, Valencia, and most dramatically Guernica — was an early demonstration of the strategic-bombing tactics that would define much of WWII.

Aftermath

Franco’s victory produced a substantially Spain-wide authoritarian Catholic-traditionalist dictatorship that would last 36 years. The post-1939 Years of Hunger killed an additional 200,000–300,000 Spaniards through famine, disease, and the continued repressive imprisonment of Republicans. Approximately 500,000 Republicans went into exile (mostly to France, Mexico, and the Soviet Union). The Republican intellectual diaspora substantially shaped post-WWII Spanish-language literature and academic life across Mexico and Latin America.

Spain remained politically isolated through the 1940s, was admitted to the United Nations in 1955 after the Cold War realignment, gradually liberalized economically during the 1960s (the Spanish Miracle), and transitioned to constitutional democracy after Franco’s death on 20 November 1975. The post-Franco transition was supervised by King Juan Carlos I (Alfonso XIII’s grandson, designated by Franco as his successor in 1969); the new democratic constitution was ratified in December 1978. Spain joined NATO in 1982 and the European Community (later European Union) in 1986.

Legacy

The Spanish Civil War was, by contemporary perception and subsequent analysis, the rehearsal for the Second World War: it produced the first European battlefield combat between fascist and democratic-leftist forces, the first substantial European aerial bombing campaign, the first organized international communist-led volunteer force (the International Brigades), and the political-ideological alignments that would shape European politics for the next three decades.

The 1939 victory of the Nationalists was the most substantial fascist political-military success in Europe before WWII. The Western democracies’ failure to support the Spanish Republic was, in retrospect, one of the most consequential single foreign-policy decisions of the 1930s and shaped the geopolitical context in which Hitler’s subsequent moves (the Anschluss, the Munich crisis, the invasion of Poland) were conducted. Modern Spanish political culture continues to be substantially shaped by the war’s unresolved memory politics; the Pact of Forgetting of the transition period was substantially revised by the Law of Historical Memory (2007) and the more recent Democratic Memory Law (2022).