Known as the Fourth or Populist Republic, the period from the end of World War II until the military coup of 31 March 1964 in Brazil brought focus on development, or the implementation of fundamental economic and social changes that would position the country for success in the 20th century. With the return of the ballot, Brazil was governed under the presidencies of Eurico Gaspar Dutra (1946-1951), Getúlio Vargas (1951-1954), João Café Filho (1954-1955), Juscelino Kubitschek (1956-1961), Jânio Quadros (1961), and João Goulart (1961-1964). Along with the new, ostensibly more democratic political regime came Brazil's new capital, Brasília, founded on April 21, 1960. Though political discussions wavered on the role of the state and foreign finances in Brazil's development, Brazil's elite generally agreed that the country should transition from a predominantly rural, agrarian and traditional society to an urban, industrial, and modern nation. Remembered for its relatively smooth democratic processes, instability remained on the horizon throughout this period. The depth of the problems facing Brazil and the intractability of divisions in the political class was epitomized by the political and personal fate of Getúlio Vargas. After returning to the presidency in 1951, Vargas stunned the nation when he shot himself on August 24, 1954. His emotional suicide note transformed him into a popular martyr, and decimated the political prospects of his most prominent enemies.

Victorious in World War II, many in the United States saw their country as the world's greatest example of economic, political, and social prosperity, factors which set it in stark contrast with its new rival, the Soviet Union. Throughout this period, US policymakers gave themselves the responsibility of distributing financial and military resources to counter the spread of communism. As the demands of the Cold War came in from all corners of the globe, strategic US foreign policy concerns gave rise to debates on the appropriate types, amounts, and recipients of foreign aid.

Consistent with the expanding influence of modernization theory and National Security Doctrine, elites in both Brazil and the United States viewed development, political stability, and anti-communism as linked goals of which the military could provide the surest safeguard. Accordingly, bilateral relations during this period resulted in U.S. loans of hundreds of millions of dollars, the expansion of Brazilian industry, and growth of American foreign investment in Brazil. While an increased presence of American financial concerns in Brazil gave the United States a larger stake in the country, the creation of a state-owned petroleum corporation in Brazil, Petróleo Brasileiro, S.A., better known as Petrobras, irked American officials by excluding the possibility of American involvement in a critical energy sector. Founded in 1949, Brazil's war college (Escola Superior de Guerra) drew significant inspiration from and interacted often with the American military as it trained officers for service. While justifying its frequent interventions in national affairs as preserving the political order, the Brazilian military put an end to the Populist Republic on March 31, 1964.

Key groups

• Escola Superior de Guerra (Brazil)
• Inter-American Economic and Social Council
• International Bank for Reconstruction and Development
• Joint Brazil-United States Defense Commission
• Joint Brazil-United States Economic Development Commission
• Organization of American States
• Petróleo Brasileiro, S.A.

Key subjects

• Brazil--Politics and government--1945-1954
• Brazil--Politics and government--1954-1964