ABC countries, or ABC powers, is a term sometimes used to describe the South American countries of Argentina, Brazil and Chile, which are seen as three of the most powerful and wealthy countries in South America. The term was mostly used in the first half of the 20th century, when they worked together to develop common interests and a coordinated approach to issues in the region with relatively little influence from outside powers, in contrast with the Cold War governments.
ABC countries Wikipedia
This is the first well-known use of the phrase 'ABC'. On May 20, 1914, the ABC countries met in Niagara Falls, Canada, to mediate diplomatically in order to avoid war between the United States and Mexico after increasing tensions over the Tampico Affair and the United States occupation of Veracruz, and developing issues that led to the Mexican Revolution. At the conference, the United States was represented by Frederick William Lehmann, a former United States Solicitor General, and Joseph Rucker Lamar, an Associate Justice of the Supreme Court of the United States.
On May 15, 1915, the ABC countries met again to sign a more formal treaty, designed to develop cooperation, nonaggression and the arbitration of disputes. It was formulated to resist United States' influence in the region and to establish mechanisms for consultation among the three signatory countries, such as setting up a permanent mediation commission. The official name was the Consultation, Non-Aggression and Arbitration Pact.
Although the treaty was not official until it was ratified by Brazil, much of the foreign policy of the three signatories between 1915 and 1930 followed the basis of consultations and mutual initiative which the ABC Pact envisaged. To this end, the press used the name "ABC Pact" when the signatory countries co-operated to pursue integration initiatives in South America, concluded official agreements or actions regarding foreign policy, or promoted ideologically and politically similar organizations within the region.
In 1942 the ABC countries and the United States mediated in the peace terms of the Ecuadorian–Peruvian War. This led to the loss of all disputed territory in the Amazon Basin that was administered by Ecuador before the war.