Workers' Party of Marxist Unification

The Workers' Party of Marxist Unification is a revolutionary Marxist party whose suppression becomes a test of the Spanish Republic’s ability to govern its own wartime rear. Its leadership is arrested and its founder, Andreu Nin, disappears in 1937; the resulting crisis reveals a struggle over political control in which clandestine repression and reliance on Soviet military aid make a clean break with Moscow seem impossible.

Identity and political setting

The party, known by the initials POUM, appears in the novel as a small but consequential force in the divided Republican camp. Its members stand outside the coalition supporting the government of Valencia and Madrid’s Defense Council, while its differences with the Communist Party and Soviet influence place it at the center of an escalating struggle over authority. The party’s importance is not measured by numbers alone: its leadership’s removal provokes anger among its Madrid adherents and attracts support from anarchists, making its repression a threat to the fragile balance in the besieged city.

The background is the Barcelona May Days of 1937. Trotskyists and anarchists fought the Generalitat’s and Republican government’s security forces for six days; more than two hundred people died, all described as antifascists. The crisis brought down Francisco Largo Caballero and led to Juan Negrín’s accession as head of government. In the aftermath, Rafael Cuesta Sánchez explains that the Republic cannot afford further internecine fighting even as suspicion and political rivalry continue to deepen.

Arrests and the disappearance of Andreu Nin

A few days before Manuel Arroyo’s return from London, the POUM’s leadership had been arrested. The arrests were retaliation, although that description was not spoken publicly. At the same time, Andreu Nin, the party’s founder and leader, had been missing since 18 June—not merely absent from public view, but unaccounted for even by the Republican government’s civilian intelligence bodies. The novel’s account makes the combination significant: an organized leadership is taken into custody while its most prominent figure vanishes beyond the reach of official inquiry.

The party’s small Madrid following reacts furiously to Nin’s disappearance. It has the support of many of the city’s anarchists, who are numerous though fewer than the socialists. Socialists themselves are divided, and the socialists and communists together are larger than the anarchist and POUM presence. Their principal shared position is support for the government in Valencia and the Madrid Defense Council, a parallel authority in the besieged capital; even that alignment is not universal. This political arithmetic helps explain why the POUM’s persecution is both a targeted attack on a small party and a destabilizing conflict across the Republican rear.

The intelligence mission in Madrid

Negrín’s account of the political situation gives the arrests their wider institutional context. He describes the Military Intelligence Service as compromised by factional struggles: Soviet advisers wield influence, communists turn a blind eye, and members of the Spanish Socialist Workers’ Party undermine one another. Meanwhile, anarchists and Trotskyists continue their own revolution, risking the war effort. Although the Madrid Defense Council had closed the city’s illegal detention centers, new ones continued to open whenever authorities shut others down.

Against this background, Arroyo is asked to return to Madrid under the false identity Rafael Cuesta Sánchez and join the Public Order Council as a government representative to the Defense Council. His assignment is to discover how many uncontrolled brigades remain active, who is conducting repression in the rear on their own initiative, whether the Military Intelligence Service has ceased to function as a Spanish service and become an extension of the Soviet secret police, and whether another crisis like Barcelona’s could occur. The position offers a formal cover for an investigation that its sponsor describes as more dangerous than fighting at the front.

The inquiry focuses on the POUM and anarchists in part because information about their organizations is reaching Valencia. At a commemoration in Madrid on 7 November, police commissioner Basilio Rodríguez warns Arroyo that whoever is behind the ongoing operation lacks the teeth for the bite they are trying to take. Rodríguez has inferred that Arroyo’s zeal in reporting on Trotskyist and anarchist groups is connected to intelligence reaching the government about those very groups. He has realized that two men cannot be conducting separate but remarkably complementary investigations at once, yet chooses not to expose Arroyo. Arroyo understands both that the commissioner has seen through the arrangement and that he will not denounce him; he also recognizes that the Rafael Cuesta Sánchez identity must leave Madrid immediately.

Soviet dependence and the party’s significance

Negrín’s account links the party’s persecution to the Republic’s dependence on the Soviet Union. He dislikes Soviet interference and would prefer to be rid of the advisers, but expelling them would mean surrendering the Republic’s only source of foreign military assistance. Without Soviet aircraft, tanks, and heavy weapons, he argues, the government would have little beyond the International Brigades’ commitment and rifles sent by Mexico. Breaking with Moscow could therefore amount to handing Spain to Francisco Franco. The novel presents opposition to Soviet control and the practical need for Soviet support not as easily reconciled principles, but as a trap that leaves the government with sharply limited choices.

That constraint gives the POUM’s fate significance beyond the arrests themselves. A government that cannot prevent secret detention, determine what its own intelligence service is doing, or establish what happened to Nin is fighting on two fronts: against Franco’s forces and against a struggle for control within its own coalition. The party’s disappearance from the political process is thus also evidence of how wartime claims of unity can conceal coercion and the suppression of dissent.

Afterlife of the repression

The novel’s later historical account identifies Nin as having been murdered by the Soviet NKVD, although the date is uncertain and probably falls in June 1937. That retrospective identification supplies an answer that the characters at the time do not possess: his disappearance was not simply an unresolved absence but a killing concealed within political repression. The gap between contemporary uncertainty and later identification reinforces the importance of information control in the novel’s treatment of the POUM.

The book also places the Republican-era use of illegal detention and concealed deaths alongside the later, systematic violence of Argentina’s military dictatorship. In Argentina, clandestine detention, torture, executions, disappearance of bodies, and the theft and reassignment of children are described as specialized parts of a state terror apparatus. The comparison does not make the episodes identical: it distinguishes the Republican rear’s factional repression from the later dictatorship’s industrialized machinery of disappearance. It does, however, make concealment itself a recurring political method—one that deprives victims of public recognition and leaves families and investigators struggling to establish what happened.