April 9, 1952 marked the start of a truly revolutionary coup d’état in Bolivia. Spurred by widespread dissatisfaction against the ruling elites, the MNR (Movimiento Nationalista Revolutionario) launched a rebellion in La Paz to challenge the status quo. The MNR already had some legitimacy among the Bolivian population as leader Paz Estenssoro had won the Presidential election the year before, but was denied his seat by General Urriolagoitia, the outgoing President. Urriolagoitia claimed that Paz Estenssoro had not in fact secured the 51 percent votes required to win the election, and instead installed a military junta to be headed by General Hugo Ballivián. The year under Gen. Ballivián saw the Bolivian people suffer under high inflation, rapidly deteriorating agricultural and mining sectors, and massive social inequities. A hunger march in the last few weeks before the revolution garnered widespread support.
On April 9, armed miners marched on La Paz, blocking troops from entering the city. The Bolivian army was demoralized and did not display much allegiance to the government. Many defected and joined the revolutionaries. After three days of fighting, the revolution was declared successful and Paz Estenssoro, who had been exiled to Argentina, returned to assume the presidency.
The new government established universal suffrage without literacy or property requirements, reduced the armed forces, nationalized the mines of the three largest tin companies, redistributed land holdings and abolished forced labor. Although the Bolivian National Revolution is monumental for mobilizing the masses and enacting far-reaching agricultural reforms, it is regarded as being ‘unfinished’, having lost momentum after a couple of years. Factionalism and in-fighting weakened the MNR, eventually leading to the dissolution of the party in 1964. Bolivia encountered severe economic problems as a result of the nationalization of mines and increased social spending. The peso, Bolivia's former currency, fell from 60 to 12,000 to the United States dollar between 1952 and 1956, creating discontent amongst the urban middle class.
Polarization between the MNR and the miners increased during the presidency of Siles Zuazo (from 1956-60), one of the founders of the MNR, who introduced a stabilization plan at the advice of the United States and the IMF. The plan included measures such as the freezing of wages and shutting down the government-subsidized miners' stores. By this time U.S. aid to Bolivia had reached its highest level, subsidizing over 30 percent of the Bolivian government's central budget. By Paz Estenssoro’s second term in 1960, the MNR had lost much of the miners’ support as a result of mass layoffs and reductions in salaries, and he began to lean increasingly on the military.
Opposition against neo-liberal policies instituted by Estenssoro to combat the dire economic situation during his fourth and final term paved the way for the election of the current Bolivian President, and head of the Movement for Socialism party, Evo Morales in 2005.