Justo participated in the conservative military coup that overthrew President Hipólito Irigoyen in 1930 and was rewarded with the presidency (1932–38). Faced by the effects of revolution, high unemployment, and the economic decline that was caused by the Great Depression, his regime was autocratic; for example, he outlawed the Communist Party in 1936. However, he supported Pan-American cooperation and closer links with Britain. He was defeated in the 1937 presidential election by Roberto Ortiz, despite having been instrumental in ending the Chaco War. A supporter of the Allies in World War II, he enlisted in the Brazilian army in 1942 and was killed.