Argentine lawyer, journalist, and politician. He played a decisive role in the Primera Junta, the first national government of Argentina, created after the May Revolution. He is considered the precursor of Argentine journalism.
Moreno’s father was Manuel Moreno y Argumosa, born in Santander, Spain, who arrived in the city in 1776 and married María del Valle. Mariano was the firstborn of the Moreno family, and had thirteen brothers. During his youth he studied Latin, logic, and philosophy at San Carlos Royal College, followed by college studies of law at Chuquisaca. During these studies, he learned the new ideas of the Spanish Enlightenment. He married María Guadalupe Cuenca and returned to Buenos Aires, becoming a prominent lawyer for the Cabildo. Unlike most other criollos, he rejected the Carlotist project and the administration of Santiago de Liniers, joining instead the ill-fated mutiny of Álzaga against him. He worked for the next viceroy, Baltasar Hidalgo de Cisneros. He wrote the economic paper The Representation of the Landowners, which persuaded the viceroy to open trade with Britain.
Although he was not prominently involved in the May Revolution that deposed Cisneros, he was appointed as secretary of war of the new government, the Primera Junta. Along with Juan José Castelli, he promoted harsh policies against the supporters of the former government and the strengthening of the new one. These policies were detailed at a secret document, the Operations plan; some historians dispute its authorship. Moreno organized military campaigns to Paraguay and Upper Peru, and ensured the execution of Santiago de Liniers after the defeat of his counter-revolution. He established the first Argentine newspaper, La Gazeta de Buenos Ayres, and translated Jean-Jacques Rousseau’s The Social Contract into Spanish.
When the Junta achieved the first military victories, President Cornelio Saavedra opposed Moreno, favoring moderate policies instead. Allied with Gregorio Funes, Saavedra expanded the number of members of the Junta to leave Morenism in a minority. With disputes still going on, Moreno was appointed to a diplomatic mission to Britain, but died at sea on the way there. His brother Manuel Moreno alleged that he was poisoned. His supporters were still an influential political party for some years after his death. Historians hold several perspectives about the role and historical significance of Moreno, from hagiography to repudiation.
He died on 4 March 1811, aged 32, in international waters.
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