MNRI-Siglo XX was founded in August 1984, after a fraction of technocrats broke away from Hernán Siles Zuazo's ruling Revolutionary Nationalist Leftwing Movement (MNRI).
[1][2] The main leader of MNRI-Siglo XX was Mario Velarde Dorado, former Minister of Foreign Affairs.
[3] The manifesto of the party declared it as seeking 'the hegemony of the working class and popular sectors in the national liberation process'.
[3] In international politics, the party claimed to represent anti-colonial and anti-imperialist viewpoints, favouring non-alignment.
[4] The National Command of MNRI-Siglo XX consisted of Mario Velarde Dorado, Franklin Anaya Vásquez, Orlando Cossio Romero, Marcelo Barrón Rondón, Reynaldo Mercado Uribe, Joaquín Monasterio Pinckert, Enrique Ipiña Melgar, Marcos Tufiño Banzer, Marcial Tamayo Sáenz, José Rivero Vargas, Jorge Rivero Vargas, Gladys San Martín de Rodríguez, María Escobar, Casta Jaimes, Sandra Urquidi Collins, Martha Arévalo, Jorge Rioja Pérez, Guido Menacho, and Guillermo Bazoberry.