Ongoing border disputes between Bolivia and Chile worsened South America's tense political environment, which was made all the more precarious by a global economic depression.

The system of mutual defense established between Bolivia and Peru sought to protect their national security and the regional balance of power by containing Chilean expansionism, which was fueled by Chile's economic ambitions over the mineral resources of the Atacama Desert.

However, territorial disagreements between Bolivia and Argentina and the possible interference of Brazil in favor of Chile prevented success.

Ever since, the treaty's usefulness, intentions, level of secrecy at the beginning of the war, and defensive nature have been subjected to debate by historians, political analysts, and politicians.

Four days after the signing of the treaty, in a secret session, the Peruvian Chamber of Deputies asked the executive[clarification needed] to purchase naval armaments.

For example, he cites the 1873 writings of the Italian author Pietro Perolari–Malmignati, who stated that the Peruvian interest in defending its nitrate monopoly against the Chilean production in Bolivia was the main cause of the secret treaty.

Moreover, to silence Brazil, Peruvian President Manuel Pardo asked Argentina and Bolivia to introduce a new clause into the protocol, complementary to the treaty, to make it clear that the Secret Treaty was aimed at not Brazil but Chile:[9][10] Soon, however, two events occurred and completely changed the state of affairs.

On 6 August 1874, Bolivia and Chile signed a new Boundary Treaty, and on 26 December 1874, the recently-built Chilean ironclad Cochrane arrived in Valparaíso.

Then, Peru realized the possibility of an unwanted Patagonian conflict and became aware of Argentina's opposition to involvement in Pacific politics except for issues regarding Chile.

For the moment, those events and the replacing of Sarmiento by Nicolas Avellaneda as President of Argentina put an end to the project of a Bolivian-Peruvian-Argentinian alliance against Chile.

In October 1875, the Peruvian foreign minister wrote to his counterpart in Buenos Aires regarding the Argentine proposals:[13][14]: 96 After the official disclosure of the pact, prior to the Chilean declaration of war in the War of the Pacific, and during the period of Peruvian mediation between Bolivia and Chile, Chile asked Peru to declare itself neutral.

[11]: 387 [15] During the failed USS Lackawanna Peace Conference in October 1880, Chile demanded the end of the secret pact.

He considers the alliance as a step further toward creating a Lima-La Paz-Buenos Aires axis, guaranteeing the peace and the stability of the American frontiers, and preventing a Chilean-Bolivian Pact that would force the loss of Antofagasta and Tarapaca to Chile and of Arica and Moquegua to Bolivia.

He thinks that the treaty might have been made to impede the use of Bolivian territories by Nicolás de Piérola to conspire against the Peruvian government.

He points out that the Bolivian-Chilean dispute on territories between 23°S and 24°S would not change Peru's neighborhood, as an intermediate Bolivian zone would remain between its and Chile's borders, including the ports of Tocopilla and Cobija.

[21] Rather than analyzing semantically the text of the treaty, Bulnes's argument rests mainly upon private and diplomatic correspondence and politicians' speeches before, during, and after the war.

Much of the information is gathered from the "Godoy papers," documents of the Peruvian Foreign Affairs Ministry that fell into Chilean hands during the occupation of Lima.

[N 1] Bulnes sees the pact as part of a Peruvian move that would oblige Chile in 1873 to submit to arbitration whatever it suited Peru, Argentina, and Bolivia so that the three would dominate the Pacific and have the territory in dispute occupied by Bolivia:[22] Since Chile, according to Peru, had this aspiration [to seize Bolivian Antofagasta], it was convenient for Bolivia to take advantage of Chile's lack of maritime forces and of the fact that Peru was in a condition to impede the mobilization of troops in defense of the disputed territory.

Bolivia was to declare that she would not respect the treaty of 1866, then in force, and should occupy the territory over which she claimed to have rights, that is to say, the salitre zone.

Relations once broken off and a state of war once declared, Chile could not obtain possession of her ironclads, and lacking force with which advantageously to attack, would find herself in the necessity of accepting the mediation of Peru, which could in case of necessity be converted into an armed mediation – if the forces of that republic sought to occupy Mejillones and Caracoles....

[28][29][30] After its disclosure, the treaty had a shocking impact on the Chilean public opinion and blocked any attempt of Peruvian mediation, whether sincere or not.