The Chaco War was a conflict that began in June 1932 when Bolivian and Paraguayan outposts clashed at a brackish lake in the northern Chaco Boreal, a territory over which the two nations disputed sovereignty. This spark began a bloody war that lasted until 1935.
The Chaco Boreal was a vast, inhospitable, and sparsely populated area bordering the two countries. In the summer (November-February) the sun parched the hot, dry earth, and in the rainy season (March-October) heavy rains created huge marshes that bred disease-carrying insects. Both Bolivia and Paraguay looked upon the Chaco as a potential site of development and wealth. Some Bolivians believed that they could regain their access to the sea, which they had lost in the War of the Pacific (1879–1883), by developing a port on the Paraguay River at the northeastern corner of the disputed territory. Much of Paraguay's foreign exchange was earned by exports of quebracho bark and cattle hides from the Chaco. In order to improve their claims to the territory, both countries had accelerated exploration and the establishment of outposts.
Although both sides had been preparing for this war for decades, neither really appreciated the logistical obstacles that they would face. As a result, prewar operational plans were useless and soon abandoned. Bolivia's situation was made significantly more difficult by the differences in strategy and priorities between President Daniel Salamanca and the country's military leaders, whose antagonism grew as the war progressed. In contrast, General José Estigarribia emerged as the de facto commander of the Paraguayan Army and won the unconditional support of recently elected President Eusebio Ayala.
Following the fighting at Lake Pitiantuta, the Bolivian army conducted a limited offensive in the east-central Chaco, capturing a number of fortines (small forts), the most important being Boquerón. Salamanca then ordered the army to suspend operations, fearing that Argentina might intervene on the side of Paraguay. Estigarribia immediately attacked Boquerón, and after a stout defense by the Bolivians, the Paraguayans captured it on 29 September. Each side sustained some 3,000 casualties.
The Bolivian public was shocked at this defeat and demanded the recall of General Hans Kundt from exile. Kundt had headed a German military mission to Bolivia prior to World War I, and following the war he returned, became a Bolivian citizen, and resumed command of the army. During the late 1920s he had been exiled for political activity. Many Bolivians believed that, as the creator of the modern army, he could win the day. In December 1932 Kundt launched a series of offensives against Paraguayan fortines, focusing on Nanawa in the east-central Chaco. Time and time again, Kundt unsuccessfully threw masses of infantry against well-prepared defensive positions. Nanawa earned the nickname the Verdun of South America. After a year of unimaginative, costly tactics, Kundt was relieved by General Enrique Peñaranda.
In October 1932 Estigarribia began his offensive, driving the Bolivians from fortín to fortín across the central Chaco. He was finally halted before Fortín Ballivián on the bank of the Pilcomayo River in the southwest corner of the Chaco. Although the fortín had no special military significance, it had become the symbol of Bolivia's presence in the Chaco. Nonetheless, General Peñaranda ordered General David Toro to abandon the fortín in order to shorten Bolivia's overstretched defenses. Toro refused to obey and Peñaranda acquiesced.
By July 1934 a large Paraguayan force commanded by Colonel Rafael Franco had driven across the central Chaco north of Ballivián and into undisputed Bolivian territory. Estigarribia realized that Franco had outdistanced his supply system and ordered him to fall back slowly. Toro, on his own initiative, decided to attempt to cut off Franco's retreating force, so he marched north with a significant part of Fortín Ballivián's garrison. Estigarribia perceived the Bolivian move and ordered Franco to fight a delaying action against Toro's superior numbers. Toro attempted to circle Franco's force but failed. Slowly, Toro was enticed farther and farther into the Chaco by the retreating Franco. Finally, in December 1934, Estigarribia rushed significant reinforcements to Franco's aid. The Paraguayans captured the wells supplying water to the Bolivians. A significant part of Toro's force was surrounded and captured. Of approximately 11,000 Bolivians, perhaps only half escaped the Paraguayan trap. In the meantime, the Paraguayans captured the now weakly defended Fortín Ballivián.
By early 1935 the Paraguayans had won almost all of the disputed Chaco and were besieging the Bolivian town of Villa Montes. But the balance of power had begun to shift in favor of the Bolivians as the Paraguayans overextended their supply lines. Also, Bolivia finally declared a general mobilization, thus taking advantage of its significantly larger population. Both sides were exhausted and nearly bankrupt. On 12 June 1935 they agreed to a cease-fire, which took effect on the 14th, and the war was formally ended in 1938.
Paraguay won most of the entire Chaco during the war and was awarded most of it during the peace negotiations. Bolivia sustained about 57,000 dead and Paraguay some 36,000. The war destroyed the fragile democratic governments in both countries: Salamanca was overthrown on 27 November 1934 and Ayala on 17 February 1936.
Angel Rodríguez, Autopsia de una guerra (1940).
Pablo Max Ynsfrán, ed., The Epic of the Chaco: Marshal Estigarribia's Memoirs of the Chaco War, 1932–1935 (1950).
David H. Zook, The Conduct of the Chaco War (1960).
Ramón César Bejarano, Síntesis de la guerra del Chaco (1982).
Farcau, Bruce W. The Chaco War: Bolivia and Paraguay, 1932–1935. Westport, CT: Praeger, 1996.
Lorini, Irma. El nacionalismo en Bolivia de la pre y posguerra del Chaco, 1910–1945. La Paz: Plural Editores, 2006.