On September 11, 1973 a military coup resulted in the death of Chile's socialist President Salvador Allende and the installation of a brutal military Junta led by Augusto Pinochet. While the Pinochet dictatorship was not the first or even the bloodiest of its kind in South America during Pinochet's reign from 1973-1988, it fomented the greatest political mobilization in Europe since 1968. My project will examine West German, British, and Spanish solidarity organizations as they transformed from more Marxist in nature, tending to employ the radical language of anti-imperialism and anti-fascism, to engendering a more "anti-political" language of human rights by the late-1970s. It will follow this opposition as it contributed to Pinochet's historic 1998 arrest in London for human rights abuse charges, issued by Spanish judge Balthasar Garzón. While legal scholars have highlighted this moment as setting the precedent for universal jurisdiction in international law, my project will historicize this moment, tracing the long-genealogy of international justice. In this way, my project will demonstrate the way that social movements can impact the structures of international law. It will also contribute to ongoing interdisciplinary debates in human rights scholarship related to the concept's transformation and widespread use in the 1970s.