Political map of South American nations 20 April 1945 (South America in World War II): Brazil was the only South American country to send troops abroad during World War II and, despite US pressure, only Bolivia and Colombia had followed its lead in declaring war on the Axis powers by the end of 1944. Nonetheless, the demands of the War economically tied South America to the Allied cause (Allies of World War II). In 1945, the continent's remaining neutral nations entered the War, becoming charter members of the United Nations.