War of the Triple Alliance (Paraguayan War)

In the last international war in the Rio de La Plata Basin (1864–1870), Paraguay opposed Brazil, Argentina, and Uruguay––the Triple Alliance. Portuguese and Spanish colonists had clashed over commercial routes and territories in the watershed since the seventeenth century. After the Spanish empire broke up, however, inland regions struggled for autonomy against pressure to unify under Buenos Aires, the port city controlling international trade. Civil wars led to political fragmentation everywhere but in Paraguay, where a centralized government emerged after independence. The intermittent blockades of navigable rivers by Buenos Aires reinforced autocracy in the small republic and spurred a military build-up starting in 1844. By the 1860s, Argentinean unification had driven tensions even higher. A confrontation that would define borders and shape nation building in the region seemed imminent. Fluctuations in regional power distribution prompted Brazilians to intervene in Uruguay in August 1864, with the tacit support of Bartolomé Mitre’s Argentinean government. Mitre wanted to consolidate Argentina’s influence in Uruguay by defeating Uruguay’s ruling Blanco party. Paraguay’s dictator, Francisco Solano López (1827–1870) saw this as a threat to the region’s balance of power. Paraguayan forces confiscated the Brazilian merchant vessel Marquês de Olinda in the Paraguayan River in November 1864. Troops invaded the Brazilian province of Mato Grosso in December 1864, and the Argentinean province of Corrientes in April 1865. Less than a month later Brazil, Argentina, and Uruguay formed the Triple Alliance. Paraguay redirected all of its national productivity and resources to support military mobilization in a desperate fight against the coalition. Solano López’s death on March 1, 1870, ended what had become a total war. Paraguay’s infrastructure was utterly destroyed and approximately 60 percent of its population was lost. Recovery took decades. Many books on the Paraguayan War have been published in Spanish or Portuguese.