On November 4, 1964, power passed from the elected leader of the Bolivian National Revolution, Víctor Paz Estenssoro, to a military junta under vice-president General René Barrientos.

[2] Barrientos, Quechua-speaking general, insisted that his assumption of power was not a counterrevolutionary move and promised to restore the Bolivian National Revolution to its "true path", from which the Nationalist Revolutionary Movement (Movimiento Nacionalista Revolucionario, MNR) had deviated during its twelve-year rule.

Barrientos encouraged the private sector and foreign investment and gave Gulf Oil Company permission to export petroleum and natural gas from Bolivia.

The defection of Barrientos's close friend and minister of interior, Colonel Antonio Arguedas, to Cuba after his announcement that he had been an agent for the United States Central Intelligence Agency (CIA) aroused national indignation.

The military also resented the crucial role of United States officers in the capture and killing of Ernesto "Che" Guevara in 1967 in Bolivia, where he had tried to start a guerrilla movement.

[2] The death of Barrientos in a helicopter crash on April 27, 1969, initially left control in the hands of his vice president, Luís Adolfo Siles Salinas (1969).

[2] Ovando (co-president, May 1965 – January 1966, and president, January–August 1966 and 1969–70) annulled the 1970 elections, dismissed the Congress, and appointed a cabinet that included independent reformist civilians who had opposed Barrientos's policies.

Disagreement over compensation, a boycott of Bolivian crude oil on the international market, and a general economic downturn became divisive factors.

While limiting United States influence in Bolivia, Torres increased cooperation with the Soviet Union and its allies in the economic and technical sectors.

Consisting mainly of representatives of workers' and peasants' organizations, the Popular Assembly was intended to serve as a base for the radical transformation of society.

They could not agree on controversial issues dealing with full worker participation in state and private enterprises, the creation of armed militias, and the establishment of popular tribunals having legal jurisdiction over crimes against the working class.

No consensus was achieved, and many delegates, resenting the lack of power to enforce the resolutions and running short of funds, returned home prematurely.

[3] Torres's hope of placating conservative opposition by avoiding radical change did not win him the support of the right, especially of the powerful business community.

[3] Colonel Hugo Banzer (1971–78), a highly respected officer who had repeatedly attempted to overthrow the regime of Juan José Torres, ruled for six years, one of the longest continuous presidential terms in recent Bolivian history.

Both parties had been enemies until the chaos of the Torres regime gave them a chance for a political comeback in alliance with conservative elements in the armed forces.

The new minister of interior, Colonel Andrés Sélich, ordered a massive crackdown on the left, abolishing labor unions and closing the universities.

On June 5, 1974, younger officers belonging to the Generational Group (Grupo Generacional) and led by General Gary Prado Salmón attempted a coup, demanding that Banzer legitimize his rule.

Influenced by the Brazilian model, he announced the complete reorganization of the Bolivian political system and the formation of a "new Bolivia" under military rule.

Banzer hoped to keep the support of the business community, the mine owners, the agricultural entrepreneurs in Santa Cruz, and the growing number of loyal bureaucrats.

The "economic miracle" turned out to be a myth; petroleum production declined sharply, and Comibol produced at a loss, despite high mineral prices, because it was subsidizing other state agencies.

[4] In 1977, with mounting opposition from civilian groups and the military and increasing pressure from the United States, Banzer announced a presidential election for 1980, hoping to remain in control.

In 1979, during the first congress of the Bolivian Labor Federation (Central Obrera Boliviana, COB) since 1970, they vehemently protested the economic austerity measures dictated by the International Monetary Fund (IMF).

In November 1978, he was overthrown in a bloodless coup by General David Padilla Arancibia, who was supported by the younger institutionalist faction of the military.

Arancibia saw the main role of the military as the defense of the country rather than political intervention and announced elections for 1979 without naming an official government candidate.

[5] The congressional ballot process was disrupted on July 17, 1980, by the violent military coup of General Luis García Meza, cousin of the deposed president Gueiler, who fled the country.

Reportedly financed by cocaine traffickers and supported by European mercenaries recruited by Klaus Barbie, former Gestapo chief in Lyon, and Stefano Delle Chiaie, Italian neo-fascist, the coup began the rule of the first Junta of Commanders of the Armed Forces, one of the darkest periods in Bolivian history.

But García Meza, who failed to gain support in the military, faced repeated coup attempts and was pressured to resign on August 4, 1981.

[5] The ruthlessness, extreme corruption, and international isolation of the García Meza government completely demoralized and discredited the military; many officers wanted to return to democracy.

When Congress reconvened on September 23, 1982, one of its first acts was to reconfirm the 1980 election results, which showed former president Hernán Siles well ahead, though short of a majority.