It was not until the 1930s that the two countries engaged in earnest as the United States attempted to mediate the Chaco War between Paraguay and Bolivia. Then, as the authors write, "hemispheric solidarity in World War II, the cold war in Latin America, the 'balance of power' among states in the Río de la Plata, and the question of U.S. support for, or aid to, Latin American dictators" became matters of mutual interest.
The dictatorship of Alfredo Stroessner (1954-89) spanned much of this era, and a shared attitude of realpolitik typified U.S.-Paraguayan relations during his rule. Post-Stroessner, the United States has stood by Paraguay during its transition to democracy, despite lingering concerns about such issues as drug trafficking and intellectual piracy. The countries should grow closer with time, the authors conclude, if Paraguay resists the continent's leftward political shift and remains a solid partner in U.S. antiterror initiatives in South America.