This article surveys the Tacna-Arica plebiscite period (1925–1926) by taking into consideration the regional history alongside increasingly important global trends. While the contest between Peru and Chile highlights the battle between primordial versus constructed nationalism, it also places contested notions of nationalism alongside a growing spirit of internationalism. Woodrow Wilson's proclamations at the end of World War I, especially his focus on self-determination and justice, directly inspired leaders in Bolivia, Chile, and Peru to seek a finalization of the Tacna-Arica dispute. Despite the hope that Wilsonian principals would win the day, traditional concepts such as economics and power proved victorious, which underscored the fragility of humanitarian rights and justice between the world wars. This investigation into how global trends influenced Tacna-Arica are placed alongside contemporary comparisons of plebiscites held in Europe between the world wars.