During the 1890s, Brazil was governed by the First Brazilian Republic, a superficial attempt at a constitutional democracy. The country was plagued by difficulties and corruption, and the Republic collapsed in 1930, replaced by a dictatorship.
After the (probably rigged) 1891 election of Deodoro da Fonseca as President, the Brazilian congress was dissolved and riots broke out. Fonesca resigned, allowing Vice President Floriano Peixoto to take power, and Peixoto started to act as dictator, leading to rebellion in government ranks. The largest of these was the Brazilian Navy, which openly opposed Peixoto, and in desperation he enlisted the help of American Mercenary forces to sail with his ships and put the rebellion down. This was not a U.S. government-approved mission, but instead one of pragmatism; the U.S. wanted Brazil to remain a Republic, and so looked the other way. However, Peixoto continued to centralize power instead of allowing free and open discourse, and a coup in 1930 began the Vargas dictatorship.