This chapter focuses on the role of copper policies in the relations between the United States and Chile during the Frei administration, especially as they relate to the developmental efforts of the Christian Democratic project. During the Frei administration, the political debate on copper policies reached a climax. Since U.S. capitals were among the most significant actors in the story, the discussions around the issue of copper converged with the ideological visions of the United States and the Cold War held by the different Chilean political parties. As the Frei administration tried to introduce the most comprehensive and consistent reform around the structure of the property of the Gran Minería del Cobre, the forces in competition in the arena of Chilean politics stood by their ideological convictions, regarding both copper and the United States, in their opposition or grudging support for the policies proposed by the Christian Democratic government. Moreover, the U.S. government became deeply involved in the matter of copper in Chile, first by pressuring the Chilean government into rolling back a price increase in 1965 and then, mostly through the personal efforts of Ambassador Edward Korry, by mediating in the negotiation between the Frei administration and Anaconda on the nationalization of the U.S. company's largest mine, Chuquicamata, in 1969.