Spanish Civil War: Largo Caballero forms a war cabinet to direct the republican war effort.

The Spanish Civil War was fought from 1936 to 1939 between the Republicans and the Nationalists. Republicans were loyal to the left-leaning Popular Front government of the Second Spanish Republic and included socialists, anarchists, communists and separatists. The opposing Nationalists who established the Spanish State were an alliance of fascist Falangists, monarchists, conservatives, and traditionalists supported by Nazi Germany and Fascist Italy and led by a military junta among whom General Francisco Franco quickly achieved a preponderant role. Due to the international political climate at the time, the war was variously viewed as class struggle, a religious struggle, or a struggle between dictatorship and republican democracy, between revolution and counterrevolution, or between fascism and communism. The Nationalists won the war, which ended in early 1939, and ruled Spain until Franco's death in November 1975.

Francisco Largo Caballero was a Spanish politician and trade unionist who served as the prime minister of the Second Spanish Republic during the Spanish Civil War. He was one of the historic leaders of the Spanish Socialist Workers' Party (PSOE) and of the Workers' General Union (UGT). Although he entered politics as a moderate leftist, after the 1933 general election in which the conservative CEDA party won the majority, he took a more radical turn and began to advocate for a socialist revolution, materialized with the failed Revolution of 1934 in Asturias.

A war cabinet is a committee formed by a government in a time of war to efficiently and effectively conduct that war. It is usually a subset of the full executive cabinet of ministers, although it is quite common for a war cabinet to have senior military officers and opposition politicians as members.

The Republican faction, also known as the Loyalist faction or the Government faction, was the side in the Spanish Civil War of 1936 to 1939 that supported the government of the Second Spanish Republic against the Nationalist faction of the military rebellion. The name Republicans was mainly used by its members and supporters, while its opponents used the term Rojos (Reds) to refer to this faction due to its left-leaning ideology, including far-left communist and anarchist groups, and the support it received from the Soviet Union. At the beginning of the war, the Republicans outnumbered the Nationalists by ten-to-one, but by January 1937 that advantage had dropped to four-to-one.