The Sandinistas did not start as Marxists. The FSLN was founded on July 23, 1961 by Carlos Fonseca, Silvio Mayorga, and Tomás Borge — three Nicaraguans radicalized by the 1959 Cuban Revolution who, in Fonseca’s 1969 manifesto “Nicaragua: Hour Zero,” insisted on fusing Marxist-Leninist organization with the specifically Nicaraguan nationalist legacy of Augusto César Sandino, the general who had fought the U.S. Marine occupation in the 1930s. The synthesis was unusual: a Marxist party whose most sacred political symbol was a nationalist hero. By July 1979, when Anastasio Somoza Debayle fled Managua, the FSLN had grown from a few dozen guerrillas in the northern mountains to a coalition commanding the capital.
The FSLN was founded on July 23, 1961, by Carlos Fonseca (1936–1976), Silvio Mayorga (1939–1975), and Tomás Borge (1930–2012), three young Nicaraguans who had been radicalized in the aftermath of the 1959 Cuban Revolution and were inspired by the Sandinista tradition. The party’s foundational document, Fonseca’s “Nicaragua: Hour Zero” (1969), argued that the FSLN had to combine Marxist-Leninist organization with a specifically Nicaraguan nationalist identity, drawing on the Sandinista legacy and the experience of the Cuban Revolution.
The FSLN spent its first two decades in the mountains and cities, building a peasant base in the northern departments of Matagalpa, Jinotega, and Nueva Segovia, and a political cadre in Managua, León, and other cities. The party was not a monolith. By 1975, it had split into three tendencies: the Guerra Popular Prolongada (GPP, or “Prolonged People’s War”) tendency, led by Fonseca, a Maoist-influenced line that emphasized rural insurgency; the Proletarian Tendency (TP), led by Carlos Alberto Torres and Jaime Wheelock, a line that emphasized the urban working class; and the Tercerista (Third Path) tendency, led by Daniel Ortega, Humberto Ortega, and Víctor Tirado, a line that emphasized broad anti-Somoza front-building. The three tendencies reunited in 1979 to lead the final offensive.
The FSLN’s political fortunes turned in 1978. The murder of Pedro Joaquín Chamorro, the editor of the opposition daily La Prensa, on January 10, 1978 produced a national uprising in which the FSLN directed a broad coalition, including the Unión Democrática de Liberación (UDEL), the Frente Amplio Opositor (FAO), the Catholic Church hierarchy, and a significant slice of the Nicaraguan business class. By 1979 the FSLN had roughly 5,000 armed combatants, several hundred thousand urban supporters, and a coherent military plan.
The final offensive began in May 1979. By June, the FSLN controlled Managua’s working-class neighborhoods, León, Estelí, Matagalpa, and most of the country’s major cities. The Organization of American States, which met in September 1978 and again in June 1979, had already recognized the legitimacy of the FSLN. The U.S. government, initially supportive of the moderate anti-Somoza forces, accepted the inevitability of an FSLN-led transition. Anastasio Somoza Debayle fled Managua on July 17, 1979, and was assassinated in Asunción, Paraguay, on September 17, 1980. The FSLN’s Junta de Gobierno de Reconstrucción Nacional, led by Daniel Ortega with Violeta Barrios de Chamorro, Moisés Hassan, Sergio Ramírez, and Alfonso Robelo, took power on July 19, 1979.
The FSLN’s first year in power was a wide-ranging reform program. The 1979 Estatuto sobre Derechos y Garantías de los Nicaragüenses codified civil liberties. A 1980 literacy campaign reduced illiteracy from 50 percent to 13 percent in seven months and won the 1980 UNESCO prize. Land redistribution, the nationalization of the banks — the formation of state farms in the former Somoza properties transformed the rural economy. By 1982, the FSLN was running a Sandinista Defense Committees (CDS) system in every neighborhood and a Sandinista Youth (JS-19) of 100,000 members, and had signed close economic and military cooperation agreements with the Soviet Union, Cuba, and the Eastern bloc.
The FSLN’s electoral history since 1979 has been: loss to Violeta Chamorro in 1990 (55% to 41%); loss to Arnoldo Alemán in 1996; loss to Enrique Bolaños in 2001; return to power in 2007 with Daniel Ortega’s 38% plurality; re-election in 2011 and 2016. The 2021 election, in which Ortega imprisoned every major opposition figure and won re-election, was widely viewed as fraudulent. The FSLN remains the dominant political force in Nicaragua, but its character has changed markedly from the broad-front, pluralist institution of 1979 to a personalist, repressive party-state.
The FSLN’s place in the Cold War was unusual: it was the only successful Marxist revolutionary movement in the Americas after Cuba, and the only one that came to power in a country with a directly contiguous U.S. strategic interest (Nicaragua is connected to the U.S. by Central America’s land bridge). For more on the Sandinistas and Contras article and the proxy wars overview.