This article examines the role of the Estonian Socialist Workers’ Party (ESTP) in the political crisis of 1934 and the coup d’état of 12 March. Although previous historiography has addressed the socialists’ support for Konstantin Päts’s authoritarian turn, the party leadership’s motives and the impact of internal party conflicts have remained insufficiently explained. The article offers a new interpretation based on previously unused sources, above all reports by Soviet diplomats stationed in Tallinn, preserved in the Archive of Foreign Policy of the Russian Federation, and an unpublished manuscript written by August Rei in 1946. These sources make it possible to substantially revise and refine existing interpretations.

The article demonstrates that the global economic crisis, the failure of government policies, and communist activities intensified divisions within the ESTP. The party’s left-wing opposition, led by Nigol Andresen, accused the leadership of excessive moderation and demanded a more radical struggle against the Veterans’ League (Vabadussõjalased), which was increasingly portrayed as a fascist threat. Internal pressure also compelled the party leadership to adopt progressively more militant anti-fascist rhetoric.

Particular attention is devoted to the Eighth Congress of the ESTP, held in February of 1934, where the conflict between the leadership and the left-wing opposition reached its climax. Although the established leadership retained control, the congress resulted in a profound split within the party. This development significantly weakened the socialists’ ability to achieve a successful outcome in the forthcoming presidential and parliamentary elections.

The newly examined sources also make it possible to reassess the role of the socialist leadership in preparing the coup of 12 March. They indicate that the party leadership actively encouraged Konstantin Päts to take decisive action. August Rei’s later account explicitly refers to a secret ‘gentlemen’s agreement’ between the socialist leaders and Päts, under which they supported the suspension of the constitution and the establishment of an authoritarian regime in order to prevent a possible Veterans’ League electoral victory. At the same time, the available evidence provides no support for claims that the Veterans themselves were planning a coup; rather, such allegations were primarily used to justify extraordinary measures.

The article concludes that the role of the Estonian socialist leadership in the establishment of the authoritarian regime was considerably greater than has previously been assumed in the historiography. Socialist support was crucial both to Päts’s seizure of power and to the legitimisation of the new regime. Fear of a possible Veterans’ League victory, combined with increasingly acute internal party tensions, led the socialist leaders to abandon democratic principles in favour of an authoritarian solution. They should therefore be regarded as important initiators and enablers of Estonia’s political coup of 1934.