In October 1982 –22 years after the end of his first term of office (1956–60)- Hernán Siles Zuazo again became President. Severe social tension, exacerbated by economic mismanagement and weak leadership, forced him to call early elections and relinquish power a year before the end of his constitutional term.
In the 1985 elections, the Nationalist Democratic Action Party (ADN) of Gen. Banzer won a plurality of the popular vote, followed by former President Paz Estenssoro's MNR and former Vice President Jaime Paz Zamora's Revolutionary Left Movement (MIR). But in the congressional run-off, the MIR sided with MNR, and Paz Estenssoro was chosen for a fourth term as President. When he took office in 1985, he faced a staggering economic crisis. Economic output and exports had been declining for several years.
Hyperinflation had reached an annual rate of 24,000%. Social unrest, chronic strikes, and unchecked drug trafficking were widespread. In 4 years, Paz Estenssoro's administration achieved economic and social stability. The military stayed out of politics, and all major political parties publicly and institutionally committed themselves to democracy. Human rights violations, which badly tainted some governments earlier in the decade, were no longer a problem. However, his remarkable accomplishments were not won without sacrifice. The collapse of tin prices in October 1985, coming just as the government was moving to reassert its control of the mismanaged state mining enterprise, forced the government to lay off over 20,000 miners.
Although the MNR list headed by Gonzalo Sánchez de Lozada finished first in the 1989 elections, no candidate received a majority of popular votes and so in accordance with the constitution, a congressional vote determined who would be president. The Patriotic Accord (AP) coalition between Gen. Banzer's ADN and Jaime Paz Zamora's MIR, the second- and third-place finishers, respectively, won out. Paz Zamora assumed the presidency, and the MIR took half the ministries. Banzer's center-right ADN took control of the National Political Council (CONAP) and the other ministries.
Paz Zamora was a moderate, center-left President whose political pragmatism in office outweighed his Marxist origins. Having seen the destructive hyperinflation of the Siles Zuazo administration, he continued the neoliberal economic reforms begun by Paz Estenssoro, codifying some of them. Paz Zamora took a fairly hard line against domestic terrorism, personally ordering the December 1990 attack on terrorists of the Néstor Paz Zamora Committee.
Paz Zamora's regime was less decisive against narcotics trafficking. The government broke up a number of trafficking networks but issued a 1991 surrender decree giving lenient sentences to the biggest narcotics kingpins. Also, his administration was extremely reluctant to pursue coca eradication. It did not agree to an updated extradition treaty with the US, although two traffickers have been extradited to the U.S. since 1992. Beginning in early 1994, the Bolivian Congress investigated Paz Zamora's personal ties to accused major trafficker Isaac Chavarria, who subsequently died in prison while awaiting trial. MIR deputy chief Oscar Eid was jailed in connection with similar ties in 1994; he was found guilty and sentenced to 4 years in prison in November 1996. Technically still under investigation, Paz Zamora became an active presidential candidate in 1996.
The 1993 elections continued the tradition of open, honest elections and peaceful democratic transitions of power. The MNR defeated the ADN/MIR coalition by a 36% to 20% margin, and the MNR's Sánchez de Lozada was selected as president by an MNR/MBL/UCS coalition in the Congress.
Sánchez de Lozada pursued an aggressive economic and social reform agenda. The most dramatic change undertaken by the Sanchez de Lozada government was the capitalization program, under which investors acquired 50% ownership and management control of public enterprises, such as the Yacimientos Petroliferos Fiscales Bolivianos (YPFB) oil-corporation, telecommunications system, electric utilities, and others. The reforms and economic restructuring were strongly opposed by certain segments of society, which instigated frequent social disturbances, particularly in La Paz and the Chapare coca-growing region, from 1994 through 1996.
In the 1997 elections, Gen. Hugo Banzer, leader of the ADN, won 22% of the vote, while the MNR candidate won 18%. Gen. Banzer formed a coalition of the ADN, MIR, UCS, and CONDEPA parties which hold a majority of seats in the Bolivian Congress. The Congress elected him as president and he was inaugurated on 6 August 1997.