The Brazilian Republican Army (Portuguese: Exército Republicano Brasileiro), also referred to as the ERB in official settings and colloquially as Os Republicanos (the Republicans) within Brazil and Los Republicanos in Colombia, Argentina and the United States, were a guerrilla force active in Brazil for most of the 1970's and 1980's, fighting in armed opposition to the military dictatorship of General Hugo Savala. The Republicano leadership was composed of members of the pre-1974 Brazilian government forced into exile in Colombia or the United States after Savala's coup that same year, and military and civilian factions loyal to them. The Republicanos were extremely skilled in sabotage, assassination and covert warfare - labelled as terrorists by both Brazil and the French government in 1976, their bases in southern and eastern Colombia were attacked by the Brazilian military in late 1977, triggering the Brazilian War.
The Republicanos narrowly survived defeat in Colombia after the United States intervened in 1978, during which time they rearmed themselves while the United States fought the brunt of the conflict. However, by the early 1980's, the United States switched from the somewhat dysfunctional left-of-center government that had initially intervened in favor of the rebels to a moderate but substantively right-of-center government committed to withdrawing from the war to focus on domestic economic concerns and pushing a policy of "Brazilianisation" of the war. After the withdrawal of the last American troops from Brazil and Colombia in December of 1983 and January of 1984, the Republicanos were greatly abetted by the similarly timed withdrawal of French support in the Brazilian dictatorship, and pushed on, capturing Salvador later that year, giving them a major seaport from which to receive American and Colombian goods. The Republicanos established the Free Republic of Brazil with a capital at Manaus and fought on until the collapse of the Brazilian government in mid-1987, which was followed by a string of rapid defeats throughout coastal Brazil and the capture of Rio de Janeiro by the Argentinean army and a regiment of Republicanos in August of 1987. The ERB fought for an additional two years to cement control over the vast, war-torn country before managing to establish a firm constitution and returning to a limited monarchy by inviting exiled monarch Pedro IV home in 1989.