The contribution examines the role of plebiscitarianism in the redefinition of Polish-German relations in the immediate aftermath of the First World War and during the interwar period. Within the framework of the Versailles order and the principle of national self-determination, plebiscites did not function as merely neutral instruments of territorial delimitation, since they took place in a context already marked by political tensions, national conflicts, and diplomatic rivalries.

Through the case of Danzig, the Upper Silesian plebiscite, and the East Prussian plebiscite, the essay shows how the question of the Polish-German border was closely connected to strategic imperatives, economic interests, and international power relations.
Particular importance is attached to the case of Upper Silesia, where uprisings, propaganda, inter-Allied intervention, and arbitration by the League of Nations highlighted the concrete limits of the principle of self-determination.

The analysis also shows how the impossibility of making ethnic and territorial borders coincide, combined with the fragile protection of minorities, contributed to the destabilization of the Versailles settlement. Plebiscitarianism thus emerges as a crucial juncture for understanding the persistent tensions in Polish-German relations up to 1939.