This chapter examines the first process of revolutionary diffusion and reactionary counter-diffusion unleashed by the Cuban Revolution. Because Castro's success inspired excessive hopes due to cognitive shortcuts, leftwing extremists across Latin America tried to replicate the armed conquest of power by initiating guerrilla movements. Ill-planned, these insurgencies were uniformly defeated by incumbent governments, which feared a replication of Castro's success and therefore unleashed their militaries. Repressive counter-insurgency caused human rights violations, but did not destroy democracy. Many governments also sought to forestall the spread of Communism with social and democratic reforms, which the US supported through the Alliance for Progress. Political regime outcomes depended on the fate of these reforms. In Venezuela and Colombia, reasonably effective reforms stabilized democracy. In Peru and Bolivia, democratic checks and balances hindered reform -- and the military eventually overthrew democracy to impose reform. In Brazil, Chile, and other SOuthern Cone countries, reform efforts paradoxically stimulated radicalization, which then provoked reactionary military coups