Of the several regional arrangements that function within the United Nations, the most elaborate in organization and function is the Organization of American States. Although the United Nations holds the primary responsibility for preserving international peace, its charter concedes virtual autonomy to regional arrangements in dealing with matters considered appropriate for regional action. This latitude stimulated a trend toward regionalism which eventually posed the important question of how to preserve legitimate regionalism like Pan-Americanism without impairing the essential overall authority of the United Nations. Following an introductory description of all existing regional arrangements, this comprehensive case study examines every aspect of security cooperation in the Western Hemisphere in the mid-twentieth century: the historical origins and development of the inter-American system; the perfecting of the security structure; and, most important, the functioning of the system under test by controversies among the member nations, and by two world wars, the Korean emergency, and the aggressive threats of international Communism. Particular attention is given to the Cuban situation. This volume was the first to recognize, boldly and imaginatively, the overwhelming influence wielded in the OAS by the powerful and wealthy United States. This elastic association of one Great Power and twenty small states, based on a mutuality of interests and a common devotion to the principles of civilized international behavior, can be said to have reached full maturity in 1948 with the adoption of the OAS charter, which articulated the goals toward which it had been striving for fifty-eight years: sovereign equality, nonintervention, and consultation for the peaceful solution of disputes and for hemisphere defense. Ironically, just when the Good Neighbor Policy and the rise of Hitler seemed to have cemented inter-American relations, breaks in the solidarity began to appear. World War II produced new forces destined to profoundly alter the bases and objectives of inter-American cooperation. The ?be good ? policy began to change to a ?do good ? policy, and in diplomatic discussions, economic measures began to eclipse those concerned with peril to the peace and security of the hemisphere.