With the increase of the U.S. economic influence in the local market during the 20th century, the level of the political and diplomatic relations between both countries was also increased. The bilateral relations were also strengthened by the convergence of regional interests. In the two first decades of the past century, the objective of the U.S. foreign policy in the region was to maintain peace and stability.
The inauguration of the Panama Canal in 1914, the establishment of new shipping companies between New York and South American ports, and the creation of a Latin American office in the U.S. Department of Commerce, contributed to a greater exchange with Peru. In this regard, in 1916, the bilateral commerce between our two countries had increased in 60%.
It was not until 1920 that the U.S. Congress elevated its Diplomatic Representation in Peru to the category of Embassy.
During the eleven year term of President Augusto B. Leguía (1919-1930), the influence of the United States was significant and it was a characteristic of the confluence of economic values between both nations, inspired by the importance of the free enterprise and commerce. For the first time, the U.S. private capital eclipsed the British investments in Peru, and trade increased significantly.
With the government of Manuel Prado there was a significant approach between Lima and Washington. While the U.S. Government was participating in World War II, it was allowed to build an airport in Talara and an increase in the cooperation between the Navies of both countries was agreed.
The administration of President Odría, who privileged U.S. investment, was one of first governments in the Western Hemisphere to sign a Treaty of Assistance and Mutual Defense with the United States in 1952. With this agreement, Peru tightened it cooperation with the United States in military affairs, which included the sponsorship of visits of Peruvian officers to U.S. military installations. Another characteristic of the relations of Peru and the United States during the Government of Odría, was the significant increase of the mineral export to the U.S. market.
The military coup d’etat in 1962 that overthrew President Prado caused an adverse and immediate reaction by the U.S. Government, with broke off diplomatic relations with Peru and denounced this act like a step backwards for the Alliance for Progress.
With the coming of the first Government of Architect Fernando Belaúnde in 1963, the diplomatic relations between Peru and the United States were normalized. Later on, the problem of La Brea and Pariñas, nevertheless, emerged like a serious controversy between Peru and the United States
With the “Revolutionary Government of the Armed Forces” installed between 1968 until the mid 1970s, a greater neutrality of Peru was observed towards the U.S. leadership in the context of the Cold War. Peru established a new political, social and economic agenda, nationalizing foreign properties. The spectrum of the diplomatic relations of Peru was broadened under the principle of ideological pluralism and universality of the diplomatic relations.