The War of the Pacific (Spanish: Guerra del Pacífico), also known by multiple other names, was a war between Chile and a Bolivian–Peruvian alliance from 1879 to 1884. Fought over Chilean claims on coastal Bolivian territory in the Atacama Desert, the war ended with victory for Chile, which gained a significant amount of resource-rich territory from Peru and Bolivia. The war demonstrated Chile's military-technological superiority over its opponents at the time.
The direct cause of the war was a nitrate taxation dispute between Bolivia and Chile, with Peru being drawn in due to its secret alliance with Bolivia. Some historians have pointed to deeper origins of the war, such as the interest of Chile and Peru in the nitrate business, a long-standing rivalry between Chile and Peru for regional hegemony, as well as the political and economical disparities between the stability of Chile and the volatility of Peru and Bolivia.
In February 1878, Bolivia increased taxes on the Chilean mining company Compañía de Salitres y Ferrocarril de Antofagasta (CSFA), in violation of the Boundary Treaty of 1874 which established the border between both countries and prohibited tax increases for mining. Chile protested the violation of the treaty and requested international arbitration, but the Bolivian government, presided by Hilarión Daza, considered this an internal issue subject to the jurisdiction of the Bolivian courts. Chile insisted that the breach of the treaty would mean that the territorial borders denoted in it were no longer settled. Despite this, Hilarión Daza rescinded the license of the Chilean company, seized its assets and put it up for auction. On the day of the auction, 14 February 1879, Chile's armed forces occupied without resistance the Bolivian port city of Antofagasta, which was mostly inhabited by Chilean miners. War was declared between Bolivia and Chile on 1 March 1879, and between Chile and Peru on 5 April 1879.
Battles were fought on the Pacific Ocean, in the Atacama Desert, the Peruvian deserts, and the mountainous interior of Peru. For the first five months, the war played out in a naval campaign, as Chile struggled to establish a marine resupply corridor for its forces in the world's driest desert. Afterwards, Chile's land campaign overcame the Bolivian and Peruvian armies. Bolivia withdrew after the Battle of Tacna, on 26 May 1880, leaving allied Peru fighting alone for most of the war. Chilean forces occupied Peru's capital Lima in January 1881. Remnants and irregulars of the Peruvian army waged a guerrilla war but could not prevent war-weary Peruvian factions from reaching a peace deal with Chile involving territorial cessions.
Chile and Peru signed the Treaty of Ancón on 20 October 1883. Bolivia signed a truce with Chile in 1884. Chile acquired the Peruvian territory of Tarapacá, the disputed Bolivian department of Litoral (turning Bolivia into a landlocked country), and temporary control over the Peruvian provinces of Tacna and Arica. In 1904, Chile and Bolivia signed the Treaty of Peace and Friendship, which established definite boundaries. The 1929 Tacna–Arica compromise gave Arica to Chile and Tacna to Peru.
The conflict is also known as the "Saltpeter War", the "Ten Cents War" (in reference to the controversial ten-centavo tax imposed by the Bolivian government), the "Nitrate War", and the "Second Pacific War". It is not to be confused with the pre-Columbian Saltpeter War, in what is now Mexico, nor the "Guano War" as the Chincha Islands War is sometimes named. The war largely settled (or set up, depending on one's point of view) the "Tacna-Arica dispute" or "Tacna-Arica controversy", and is sometimes known by that name as well, although the details took decades to resolve.
Wanu (Spanish: guano) is a Quechua word for fertilizer. Potassium nitrate (ordinary saltpeter) and sodium nitrate (Chile saltpeter) are nitrogen-containing compounds collectively referred to as salpeter, saltpetre, salitre, caliche, or nitrate. They are used as fertilizer, but have other important uses. Saltpeter is used to make gunpowder.
Atacama is a Chilean region south of the Atacama Desert, which mostly coincides with the disputed Antofagasta province, known in Bolivia as Litoral.
When most of South America gained independence from Spain and Portugal in the 19th century the demarcation of frontiers was uncertain, particularly in remote, thinly populated portions of the newly independent nations. Bolivia and Chile's Atacama border dispute, in the coastal territories between approximately the 23° and 24° South parallels, was just one of several longstanding border conflicts that arose in South America.
Cobija, Paposo, Mejillones and the territory of Antofagasta appears on a 1793 map of Andrés Baleato and the 1799 map of the Spanish Navy as inside the jurisdiction of Chile, pointing out the Loa River as an internal limit of the Spanish Empire between Chile and Peru, leaving Charcas without sea access.
The dry climate of the Peruvian and Bolivian coasts had permitted the accumulation and preservation of vast amounts of high-quality guano deposits and sodium nitrate. In the 1840s, Europeans knew the value of guano and nitrate as fertilizer and the role of saltpeter in explosives. The Atacama Desert became economically important. Bolivia, Chile, and Peru were in the area of the largest reserves of a resource demanded by the world. During the Chincha Islands War (1864–1866), Spain, under Queen Isabella II, attempted to exploit an incident involving Spanish citizens in Peru to re-establish its influence over the guano-rich Chincha Islands.
Starting from the Chilean silver rush in the 1830s, the Atacama was prospected and populated by Chileans. Chilean and foreign enterprises in the region eventually extended their control to the Peruvian saltpeter works. In the Peruvian region of Tarapacá, Peruvians were a minority, behind both Chileans and Bolivians.
Bolivia and Chile negotiated the "Boundary Treaty of 1866," or the "Treaty of Mutual Benefits," which established 24° S "from the littoral of the Pacific to the eastern limits of Chile" as the mutual boundary. Both countries also agreed to share the tax revenue from mineral exports from the territory between 23° and 25° S. The bipartite tax collecting caused discontent, and the treaty lasted for only eight years.
Secret Treaty of Alliance of 1873
In February 1873, Peru and Bolivia signed a secret treaty of alliance against Chile. The last clause kept it secret as long as both parties considered its publication unnecessary, until it was revealed in 1879. Argentina, long involved in a dispute with Chile over the Strait of Magellan and Patagonia, was secretly invited to join the pact, and in September 1873, the Argentine Chamber of Deputies approved the treaty and 6,000,000 Argentine peso for war preparations. Eventually, Argentina and Bolivia did not agree on the territories of Tarija and Chaco, and Argentina also feared an alliance of Chile with Brazil. The Argentine Senate postponed and then rejected the approval, but in 1875 and 1877, after border disputes with Chile flared up anew, Argentina sought to join the treaty. At the onset of the war, in a renewed attempt, Peru offered Argentina the Chilean territories from 24° to 27° S if Argentina adhered to the pact and fought in the war.
Historians including G. Bulnes, Basadre, and Yrigoyen agree that the real intention of the treaty was to compel Chile to modify its borders according to the geopolitical interests of Argentina, Peru, and Bolivia, as Chile was militarily weak before the arrival of the Chilean ironclads Almirante Cochrane and Blanco Encalada.
Chile was not informed about the pact until it learned of it, at first cursorily by a leak in the Argentine Congress in September 1873, when the Argentine Senate discussed the invitation to join the Peru-Bolivia alliance. The Peruvian mediator Antonio de Lavalle stated in his memoirs that he did not learn of it until March 1879, and Hilarion Daza was not informed of the pact until December 1878.