Unfulfilled Plans of Triple Occupation of Carpatho-Ukraine by the Armed Forces of Hungary, Poland, and Romania in March 1939

Drawing on previously unknown diplomatic documents from Polish archives, the article explores a little-known episode in the history of state-territorial changes in Subcarpathian Rus’ (Carpatho-Ukraine) in mid-March 1939, specifically Warsaw’s plans to implement a scenario of triple occupation of the region involving Hungary, Romania, and Poland. The study reveals that Polish diplomacy and the military first articulated the idea of transferring the southeastern part of Transcarpathia, along with the strategically important railway line Yasinya-Sighetu Marmației, under Romanian control in early October 1938. These plans were related to Warsaw’s attempts to neutralize Romanian military-political opposition to the creation of a common Polish-Hungarian frontier in the Carpathians, achieve wider Hungarian-Romanian rapprochement, and strengthen the military-political alliance with Bucharest against the USSR. These efforts were part of a broader geopolitical project of the Second Polish Republic to establish its own sphere of influence in East-Central Europe under the «Third Europe» («Intermarium») brand. In Transcarpathia, the interests of key regional players — Poland, Hungary, and Romania — intersected. The culmination of Warsaw’s efforts to implement this project coincided with the final dismantling of Czecho-Slovakia in mid-March 1939, when the Polish military and political leadership proposed a triple occupation of Carpatho-Ukraine. This plan involved the participation of Poland’s armed forces in establishing control over the Yasinya-Sighetu Marmației railway line and separating Hungarian and Romanian troops. However, Warsaw’s attempts to seize the initiative in shaping the region’s fate from Berlin and Budapest and reorganize it according to its vision failed. Instead, these efforts provoked heightened tensions between Hungary and Romania, threatening to trigger a continental war. Ultimately, the failure of Warsaw’s plans dashed Polish diplomacy’s hopes for the creation of the «Third Europe» project, while Germany benefited the most from the increased frictions between Hungary and Romania.