The Inter-American Conference at Havana, Cuba
Between April and July 1940 the war in Europe forced the United States to grapple with two related issues: (1) the fate of the Western Hemisphere possessions of the European powers conquered or endangered by Germany; and (2) the United States' vital need of for additional bases in the Caribbean and the Atlantic in order to counter a possible Axis advance on the New World.
The defense of the Western Hemisphere was the central concept in the RAINBOW plans which United States planners had developed on the eve of the outbreak of World War II. RAINBOW 1, which was the only one of the five to have been completed and approved by September 1, 1939, assumed that, in the event of aggression in Europe by the Axis powers, Britain and France as well as the American republics and Canada would remain neutral. The United States would then be left to defend its security and other interests via a sort of "fortress" strategy that envisaged the use of base facilities in some of the European powers' territories in the Caribbean. On the other hand, RAINBOW 4 was based on the calculation of the military collapse of the Western European democracies before the German-Italian Axis, and of a resultant potential transatlantic threat by the Axis to the United States and the entire American hemisphere. In such a contingency, the plan laid out a total hemispheric defense strategy by the United States, with the Caribbean again holding a key position.
In the end, the assumption of RAINBOW 1 did not materialize. Rather than appease German aggression, Britain and France took up the challenge of war, including the war at sea in the Atlantic against the German surface and underwater fleet. Behind this front-line naval shield, the United States Navy, in cooperation with Caribbean/Western Atlantic sections of the Anglo-French navies and within the limits of a very nonneutral Security Zone, defended the Caribbean area and the approaches to the Panama Canal, which was the rapid transit route for the bulk of its forces in the Pacific facing Japan. This state of affairs in the winter of 1939 and the first quarter of 1940 produced a sense of false security in the United States. The result was that in the