Under the Lyndon B. Johnson administration, the US took a more hardline stance on Latin America—sometimes called the "Mann Doctrine". In 1964, the Brazilian military overthrew the government of president João Goulart with US backing. In late April 1965, the US sent some 22,000 troops to the Dominican Republic in an intervention, codenamed Operation Power Pack, into the Dominican Civil War between supporters of deposed president Juan Bosch and supporters of General Elías Wessin y Wessin, citing the threat of the emergence of a Cuban-style revolution in Latin America. The OAS also deployed soldiers to the conflict through the mostly Brazilian Inter-American Peace Force. Héctor García-Godoy acted as provisional president, until conservative former president Joaquín Balaguer won the 1966 presidential election against non-campaigning Juan Bosch. Activists for Bosch's Dominican Revolutionary Party were violently harassed by the Dominican police and armed forces.