The Chaco War (1932-1935) was a vicious armed conflict between Bolivia, which had ties with monopolies in the USA, and Paraguay, which was dependent on Great Britain. It took place from 1932 to 1935 in what is today western Paraguay and the eastern portion of Bolivia. This region is known as 'Chaco', which is semi-arid and covered by scrub forests of stunted trees and shrubs. This armed struggle was caused by a territorial dispute and the discovery of oil. The war was definitely ended by a peace treaty that granted Paraguay about two-thirds of the contested territory.
The Chaco War was fought over a disputed border region in the Chaco, where petroleum deposits had been discovered in the 1920’s. Since Bolivia is a landlocked country, it wanted full control of the whole of the Chaco region in order to have access to the Paraguay River and, hence, to the Atlantic Ocean, via Rio de La Plata. Armed clashes between the two countries had already taken place as early as 1927, and full war broke out in July 1932. During the war, the United States openly supported, and supplied arms to Bolivia. Great Britain, on the other hand, did the same, providing Paraguay with infantry weapons, such as Lee-Metford rifles, Maxim and Vickers machine guns, and Stokes mortars. Both countries had also acquired the Argentine Mauser M1891 and M1909. By June 1934, Paraguay controlled most of the disputed territory.
The battles of Boqueron, Campo Jordan, and Second Nanawa were the most fiercely fought military engagements of the war. Both sides suffered heavy casualties, with a total of 270,000 being killed or wounded. The Chaco War exhausted the financial resources of both countries and sharply aggravated their internal political situations. In June 1935, after mediation by the United States, Argentina, Brazil, Chile, Peru, and Uruguay, a truce and a ceasefire was declared. The peace treaty of July 1938 gave Paraguay most of the territory at issue. By the 1940’s, however, the area would be controlled by US oil monopolies.
 |
| Above, the Bolivian Army marching into the Chaco region in 1932. |
 |
| Paraguayan infantry soldiers serving an 81-mm Stokes mortar during the Battle of Boqueron. |
 |
| Map of Paraguay. The disputed area is in pink. |