Consequences of the war 

Following Paraguay's final defeat in 1870, Argentina sought to enforce one of the secret clauses of the Triple Alliance Treaty, according to which Argentina would receive a large part of the Gran Chaco, a Paraguayan region rich in quebracho (a product used in the tanning of leather). The Argentinian negotiators proposed to Brazil that Paraguay should be divided in two, with each of the victors incorporating a half into its territory. The Brazilian government, however, was not interested in the end of the Paraguayan state, since it served as a cushion between the Brazilian Empire and Argentina.

A standstill began, and the Brazilian army, which was in complete control of the Paraguayan territory, remained in the country for six years after the final defeat of Paraguay in 1870, only leaving in 1876 in order to ensure the continued existence of Paraguay. During this time, the possibility of an armed conflict with Argentina for control over Paraguay became increasingly real, as Argentina wanted to seize the Chaco region, but was barred by the Brazilian Army.

Rutherford B. Hayes

No single overall peace treaty was signed. The post-war border between Paraguay and Argentina was resolved through long negotiations, finalized in a treaty that defined the frontier between the two countries signed on February 3, 1876 and which granted Argentina roughly a third of the area it had intended to incorporate originally. The only region about which no consensus was reached — the area between the Río Verde and the main branch of Río Pilcomayo — was arbitrated by U.S. President Rutherford B. Hayes, who declared it Paraguayan. (The Paraguayan department Presidente Hayes was named after Hayes due to his arbitration decision.) Brazil signed a separate peace treaty with Paraguay on January 9, 1872, obtaining freedom of navigation on the Río Paraguay. Brazil received the borders it had claimed before the war. The treaty also stipulated a war debt to the imperial government of Brazil that was eventually pardoned in 1943 by Getúlio Vargas in reply to a similar Argentine initiative

In December 1975, when the presidents Ernesto Geisel and Alfredo Stroessner signed in Asunción a Treaty of Amity and Cooperation, the Brazilian government returned its spoils of war to Paraguay.

The war still remains a controversial topic - especially in Paraguay, where it is considered either a fearless struggle for the rights of a smaller nation against the aggressions of more powerful neighbours, or a foolish attempt to fight an unwinnable war that almost destroyed a whole nation. In Argentina, as the war wore on, many Argentines saw the conflict as Mitre's war of conquest, and not as a response to aggression. They remembered that Solano López, believing he would have Mitre's support, seized the opportunity to attack Brazil created by Mitre, when he used the Argentinian Navy to deny access to the River Plate to Brazilian ships in early 1865, thus starting the war.

The Paraguayan villages destroyed by the war were abandoned and the peasant survivors migrated to the outskirts of Asunción, dedicating themselves to subsistence agriculture in the central region of the country. Other lands were sold to foreigners, mainly Argentines, and turned into estates. Paraguayan industry fell apart. The Paraguayan market opened itself to British products and the country was forced for the first time to get outside loans - totalling a million British pounds. In fact, Britain can be seen as the power that most benefited from the war: whilst the war ended the Paraguayan threat to their interests, Brazil and Argentina fell into massive debt, establishing a pattern that continues to this day. (Brazil repaid all British loans by the Getúlio Vargas era.)

Argentina annexed part of Paraguayan territory and became the strongest of the River Plate countries. During the campaign, the provinces of Entre Rios and Corrientes had supplied Brazilian troops with cattle, foodstuffs and other products.

Brazil paid a high price for victory. The war was financed by the Bank of London, and by Baring Brothers and N M Rothschild & Sons. During the five years of war, Brazilian expenditure reached twice its receipts, causing a financial crisis.

In total, Argentina and Brazil annexed about 140,000 km² (55,000 square miles) of Paraguayan territory: Argentina took much of the Misiones region and part of the Chaco between the Bermejo and Pilcomayo rivers; Brazil enlarged its Mato Grosso province by claiming territories that had been disputed with Paraguay before the war. Both demanded a large indemnity (which was never paid) and occupied Paraguay until 1876. Meanwhile, the Colorados had gained political control of Uruguay, which they retained until 1958.

Slavery was undermined in Brazil as slaves were freed to serve in the war. The Brazilian army became a new and expressive force in national life. It transformed itself into a strong institution that, with the war, gained tradition and internal cohesion and would take a significant role in the later development of the history of the country.

Emperor Don Pedro

The war took its biggest toll on the Brazilian emperor. The economic depression and the fortification of the army would later play a big role in the deposition of the emperor Dom Pedro II and the republican proclamation in 1889. General Deodoro da Fonseca would become the first Brazilian president.

There are some scholars who claim that the War of the Triple Alliance cut short Paraguay’s promising future. These writers argue that Paraguay’s protectionist economy and nationalist ambitions threatened Great Britain’s system of global trade, because the superpower feared other Latin American countries would imitate Paraguay’s actions. As a result, Britain supported the Allies' war effort by financing it. Some even go so far as to claim Britain instigated the entire conflict. However, there is little empirical data to support the latter assertion.