Why did so many Latin American leftists believe they could replicate the Cuban Revolution in their own countries, and why did so many rightists fear the spread of Communism? Cognitive-psychological insights about people’s distorted inferences and skewed interest calculations explain why the left held exaggerated hopes and why the right experienced excessive dread. The resulting polarization provoked a powerful backlash in which the right uniformly defeated the left. To forestall the feared spread of revolution, the military in many countries imposed authoritarian regimes and brutally suppressed left-wingers. Overly worried about the advance of Cuban-inspired radicalism as well, the United States condoned and supported the installation of dictatorship, but Latin American elites took the main initiative in these regressive regime changes. With a large number of primary and secondary sources, this book documents how the misperceptions on both sides of the ideological divide thus played a crucial role in the frequent destruction of democracy.