Chile and Brazil have acted numerous times as mediators in international conflicts, such as in the 1914 diplomatic impasse between the United States and Mexico, avoiding a possible state of war between those two countries.

[1] During much of the 19th and the 20th centuries, conflicts with Argentina over Uruguay and Paraguay on behalf of Brazil and over Patagonia on behalf of Chile made Brazil and Chile close allies.

During the War of the Pacific, with Chile fighting against Peru and Bolivia, Brazil provided tacit support for Chile, and forced Argentina, which attempted to join the Peruvian–Bolivian alliance, to stay neutral throughout the war.

On May 20, 1914, Argentina, Brazil and Chile (the ABC countries) met in Niagara Falls, Canada, to mediate diplomatically to avoid a state of war between the United States and Mexico over the Veracruz Incident and the Tampico Affair.

It was formulated to resist American influence in the region and to establish a mechanism for consultation among the three signatory countries, such as by setting up a permanent mediation commission.