Jornadas de Mayo de 1937

The May Days of 1937 were six days of fighting in Barcelona that laid bare the fractures within the Republican camp during the Spanish Civil War. The clashes left more than two hundred dead, all antifascists, and were followed by political upheaval and intensified suspicion: the government’s effort to hold its coalition together coexisted with the detention of the Workers' Party of Marxist Unification leadership and the disappearance of Andreu Nin.

Causes and Political Context

In early May, Trotskyists and anarchists confronted the forces of law and order belonging to the Government of Catalonia and the Republican government. The insurgents proclaimed a revolution, but after six days of fighting they were defeated. The casualties were not Francoist opponents but members of the Republican side itself, a measure of how the conflict turned inward even as the war against Franco continued.

The crisis brought down Francisco Largo Caballero and Negrín’s rise to the presidency of the government. That change did not resolve the divisions behind the fighting. The Republican authorities faced a choice shaped by the need for Soviet military assistance: breaking with Soviet advisers risked losing the only available source of aircraft, tanks, and heavy weapons, while retaining their influence carried its own political costs.

Arrests and Disappearance

The arrests of the POUM leadership followed the May fighting. The arrests were presented publicly without being acknowledged as retaliation, but the account describes them as a reprisal. Among those seized was Andreu Nin, the party’s leader. He disappeared on the eighteenth, and even the Republican government’s civilian intelligence bodies could not establish his whereabouts.

The detentions and Nin’s disappearance extended the crisis beyond the street battles. In Madrid, the news angered the few POUM supporters in the capital, who had the backing of many local anarchists. Socialists, more numerous but divided among themselves, and socialists and communists aligned in support of the government in Valencia and Madrid’s Defense Council, though that alignment was narrow and incomplete.

Consequences and Significance

By the time Manuel Arroyo Benítez arrived in Madrid in June, the divisions exposed by the Barcelona fighting had become part of the city’s political landscape. The competing factions differed over the government, the Soviet presence, and the continuing activities of illegal detention centers. The May Days had been put down, but their aftermath made clear that defeat in Barcelona had not restored trust or settled who could exercise authority in the Republican rear.

The event thus joins battlefield losses to a crisis of political legitimacy within the Republic. The same government that depended on Soviet aid confronted accusations of Soviet influence; the suppression of an internal revolt was followed by arrests and an unresolved disappearance. With more than two hundred antifascists dead and Nin missing, the struggle against Franco was shadowed by violence among those fighting on the same side.