The primary objective of this article is to investigate the Ukrainian context within Polish foreign policy during the immediate post-World War I years, with a particular focus on the period 1919–1920. The intertwined processes of state-building, territorial negotiations, and military alliances between the Ukrainian People’s Republic (UPR) and the Second Polish-Lithuanian Commonwealth, that shaped the geopolitical and security landscape of Eastern Europe, are examined.

A novel analysis is provided of the multifaceted diplomatic and military interactions that defined Polish-Ukrainian relations during this turbulent era. The article highlights the spectrum of approaches – from proposals for territorial concessions in exchange for military support to staunch resistance against compromising Ukrainian sovereignty – and emphasizes how divergent positions within both Ukrainian and Polish political circles influenced the negotiations. It also situates these debates within the broader international context, underscoring the impact of external forces such as the Entente and emerging Soviet interests.

The methodology employed in this study involves a comprehensive review and analysis of primary sources – including diplomatic correspondence, treaty documents, and contemporary political writings – as well as secondary literature that contextualizes these events. This multifaceted approach allows for a detailed examination of the shifting alliances, internal divisions, and strategic compromises that characterized the negotiations between the UPR and Poland, and situates these developments within the larger framework of interwar Eastern European state-building.

The article investigates and clarifies the intricate nature of the Polish-Ukrainian negotiations, revealing that the process was deeply affected by conflicting visions within the Ukrainian leadership and contrasting factions in Polish politics. It finds that while some Ukrainian leaders were prepared to make significant territorial concessions in exchange for vital military support, others decried such compromises as detrimental to national integrity. Simultaneously, Polish policymakers wrestled with balancing nationalist ambitions against pragmatic security concerns, a tension further complicated by pressures from the Entente and Soviet advances.

By shedding light on these dynamics, the article contributes to a deeper understanding of the historical complexities underlying Polish-Ukrainian relations and the broader strategic and ideological currents of post-war Eastern Europe. Its insights into the interplay between military exigencies, diplomatic maneuvering, and internal political debates offer a fresh perspective on the challenges of state-building and interethnic relations during the interwar period.

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