The resignation of Francisco Largo Caballero on May 17, 1937, followed the tensions that erupted during the Barcelona May Days, where violent confrontations between workers’ factions highlighted the fractious relationships among the leftist groups in Spain. Caballero's government, which was seen as increasingly unable to unify the various factions due to rising internal discord, faced criticism for its failure to effectively manage the war effort against Franco's Nationalists. Heightened concerns around the centralization of power and the role of anarchists within the coalition government pushed for a change in leadership.

In the aftermath, Juan Negrín, a moderate socialist, took over the leadership, emphasizing a doctrine of unity against the fascist threat. Negrín's government aimed to consolidate authority and redirect efforts to enhance the defense against Franco's forces. Importantly, his formation of a government without the anarcho-syndicalist Confederación Nacional del Trabajo (CNT) signaled a strategic pivot that sought to strengthen the Republican front by sidelining radical elements who had been critical of centralized control.

The exclusion of the CNT was not merely a political maneuver; it represented the ideological divide within the left regarding how the war should be fought and what post-war Spain should resemble. This reshaping of government would have long-lasting implications for the dynamics of the Spanish Republic, reflecting broader questions about the future of socialism and anarchism in Spain and the necessity for unity in wartime, albeit with contentious bargaining between factions.