In April 1949, Portugal, an undemocratic and underdeveloped small country of Western Europe, became one of the 12 founding members of the Atlantic Alliance. The important geopolitical position of the Portuguese Atlantic islands was the main justification for the admission of this authoritarian regime in the Western Alliance. From this moment on, North Atlantic Treaty Organization (NATO) served as a framework for the bilateral relationship between Portugal and the USA. The US interests were fully achieved after the Azores agreement of 1951, since it authorised Washington to use an airbase in the archipelago during peacetime. However, for Lisbon, NATO did not safeguard one of its most important objectives: the maintenance of its colonial empire. As the 1950s evolved, US presence in the Azores and Lisbon's resistance to decolonisation became increasingly interdependent. Portugal quickly understood that the Azores could be a trump card to obtain political leverage from the USA regarding Lisbon's colonial policy. This strategy led to the establishment of a modus vivendi in US-Portuguese relations that was based on a thin balance between the interests of both governments.
- Cold War