What were the effects of FDR’s Good Neighbor policy during World War II?
The positive relationships and cooperation between the United States and the countries of Latin America provided a basis for support of the Allied war efforts during World War II by the countries of Central and South America. Treaties signed before the United States entered active involvement pledged all the signers to cooperate and support each other's efforts.
Once the United States entered the fighting, the Latin American nations did offer support through supplies of needed resources and materials, through offering locations for military bases, and through increased prosecution of Axis sympathizers in the Latin American countries. Argentina initially resisted joining in this support of the Allies; it was eventually pressured into doing so, which did go against the pledges of noninterference that had been put into practice under the Good Neighbor Policy.