Solano López accurately assessed the September 1864 Brazilian intervention in Uruguay as a slight to the region’s lesser powers. He was also correct in his assumption that neither Brazil nor Argentina paid much attention to Paraguay’s interests when they formulated their policies.
He said that preserving Uruguayan “independence” was crucial to Paraguay’s future as a nation. Consistent with his plans to start a Paraguayan “third force” between Argentina and Brazil, Solano López committed the nation to Uruguay’s aid.
When Argentina failed to react to Brazil’s invasion of Uruguay, Solano López seized a Brazilian warship in November 1864. He followed this move with an invasion of Mato Grosso, Brazil, in March 1865, an action that proved to be one of Paraguay’s few successes during the war.
Solano López then struck at his enemy’s main force in Uruguay; he was, however unaware that Argentina had acquiesced to Brazil’s Uruguay policy and would not support Paraguay against Brazil.
Argentina refused Solano López’s request for permission for his army to cross Argentine territory to attack the Brazilian province of Río Grande do Sul, Undeterred, Solano López sent his forces into Argentina. This action set the stage for the May 1865 signing by Argentina, Brazil, and Uruguay (now reduced to puppet status) of the Treaty of the Triple Alliance. Under the treaty, these nations vowed to destroy Solano López’s government.
Paraguay was in no sense prepared for a major war, let alone a war of the scope that Solano López had unleashed. In terms of size, Solano López’s 30,000-man army was the most powerful in Latin America but the army’s strength was illusory because it lacked trained leadership, a reliable source of weapons and adequate reserves. Since the days of El Supremo, the officer corps had been neglected for political reasons.
The army suffered from a critical shortage of key personnel, and many of its fighting units were undermanned. Paraguay lacked the industrial base to replace weapons lost in battle, and the Argentine-Brazilian alliance prevented Solano López from receiving arms from abroad.
Paraguay’s population was only about 450,000 in 1865, a figure lower than the number of people in the Brazilian National Guard, and amounted to less than one-twentieth of the combined allied population of 11 million.
Even after conscripting every able-bodied man for the front, including children as young as ten, and forcing women to perform all nonmilitary labor, Solano López still could not field an army as large as those of his rivals.
Apart from some Paraguayan victories on the northern front, the war was a disaster for Solano López. The core units of the Paraguayan army reached Corrientes in April 1865.
By July, more than half of Paraguay’s 30,000-man invasion force had been killed or captured along with the army’s best small arms and artillery. The war quickly became a desperate struggle for Paraguay’s survival.
Paraguay’s soldiers exhibited suicidal bravery, especially considering that Solano López shot or tortured so many of them for trivial offenses. Cavalry units operated on foot for lack of horses. Naval infantry battalions armed only with machetes attacked Brazilian ironclads. The suicide attacks resulted in fields of corpses. Cholera was rampant.
By 1867, Paraguay had lost 60,000 men to casualties, disease, or capture, and another 60,000 soldiers were called to duty. Solano López conscripted slaves, and infantry units formed entirely of children appeared. Women were forced to perform support work behind the lines.
Clothing shortages were so severe that Paraguayan troops went into battle semi-nude, and even colonels went barefoot, according to one observer.
The defensive nature of the war, combined with Paraguayan tenacity and ingenuity and the difficulty that Brazilians and Argentinians had cooperating with each other, rendered the conflict a war of attrition. In the end, Paraguay lacked the resources to continue waging war against South America’s giants.
As the war neared its inevitable denouement, Solano López’s grip on reality loosened further. Imagining himself surrounded by a vast conspiracy, he ordered thousands of executions in the military. In addition, he executed two of his brothers and two brothers-in-law, scores of top government and military officials, and about 500 foreigners, including many diplomats.
He frequently had his victims killed by lance thrusts to save ammunition. The bodies were dumped into mass graves. His cruel treatment of prisoners was proverbial. Solano López condemned troops to death if they failed to carry out his orders to the minutest detail. “Conquer or die” became the order of the day.
Solano López’s hostility even extended to United States Ambassador to Paraguay Charles Ames Washburn. Only the timely arrival of the United States gunboat Wasp saved the diplomat from arrest.
Allied troops entered Asunción in January 1869, but Solano López held out in the northern jungles for another fourteen months until he finally died in battle. 1870 marked the lowest point in Paraguayan history.
Hundreds of thousands of Paraguayans had died. Destitute and practically destroyed, Paraguay had to endure a lengthy occupation by foreign troops and cede large patches of territory to Brazil and Argentina.
Despite several historians’ accounts of what happened between 1865 and 1870, Solano López was not wholly responsible for the war. Its causes were complex and included Argentine anger over Antonio López’s meddling in Corrientes.
The elder López also had infuriated the Brazilians by not helping overthrow Rosas in 1852 and by forcing Brazilian garrisons out of territory claimed by Paraguay in 1850 and 1855. Antonio López also resented having been forced to grant Brazil free navigation rights on the Río Paraguay in 1858.
Argentina meanwhile disputed ownership of the Misiones district between the Río Paraná and Río Uruguay, and Brazil had its own ideas about the Brazil-Paraguay boundary. The Uruguayan vortex compounded these problems. Carlos Antonio López had survived mainly with caution and a good bit of luck; Solano López had neither.