Contrary to widely held progressive expectations, during certain time periods authoritarian rule – not democracy – has spread across countries in striking waves. The article examines the causal mechanisms driving these diffusion processes. Focusing on Europe and Latin America, it argues that waves of authoritarianism constituted primarily processes of counter-diffusion, namely reactionary efforts to forestall the spread of revolutionary impulses. As first the Russian Revolution and then the Cuban Revolution stimulated emulation efforts by radical leftists in many countries, right-wingers and even centrist sectors sought to immunize the body politic against the Communist virus by embracing authoritarianism and corporatism, if not fascism.

Right-wingers’ fears and their disproportionate response to leftist challenges reflected core mechanisms of bounded rationality. Political actors do not process events in a careful and systematic way, but rely on inferential shortcuts, which induce people to overrate the significance of dramatic, vivid events and to draw surprisingly firm conclusions from limited data, including a single outstanding occurrence. Accordingly, the left overestimated the replicability of the Russian and Cuban Revolutions, and so did the right. As leftists started many uprisings, rightists squashed them with brutal force and sought to prevent Communist revolution by embracing reactionary rule. These harsh reactions were driven by disproportionate loss aversion. This mechanism documented by cognitive psychologists seriously skewed political decisions and, given the prevailing fear of Communism, set in motion waves of rightwing autocracy.