Resumen: Many authors have argued that the countries of the Southern Cone almost went to war against one another in the decade of the 1970s due to the existence of military dictatorships in most of them. A tension existed between ideological affinities and geopolitical, na-tionalist, and territorial legacies that dated back to the nineteenth cen-tury and reemerged in the twentieth. The 1970s was one of these occa-sions. Although references to this situation abound, there does not exist any in-depth studies of this phenomenon. This article represents a first piece of the puzzle. It is based on Chilean primary sources and is com-plemented by records from the United States, England, and the two Germanies. Chile confronted a situation of international isolation as a result of a world-wide reaction to the coup d’état and the dictatorship. The situation grew increasingly complex and precarious due to the on-going possibility of international conflict.