World War II became a global conflict at the end of 1941 / beginning of 1942, affecting all sovereign states on the planet. On the American continent, U.S. hegemony implied the building of a homogeneous power bloc made up of all independent Latin American republics, which broke diplomatic relations with the Axis Powers until the end of January 1942, with the exception of Argentina and Chile. Thenceforth, the German and Italian submarine warfare carried out in the North Atlantic against the Allies expanded to the coast of the American continent, affecting all commercial shipping there. Its unrestricted nature largely accounts for the moments of Mexico's and Brazil's declaration of war. Argentina was an exception, with its ships spared, despite some attacks. Therefore, it could keep its neutrality. The paper, with its systemic view, counters domestic and personalistic explanations about the respective declarations of war and the neutrality of the countries examined.