This excluded leftist political organizations, prompting the formation of guerrilla groups like FARC, ELN, and the EPL in the 1960s followed by the April 19 Movement (M-19) in the 1970s.

On 3 March 1989 an attack at El Dorado airport led to the death of Patriotic Union leader José Antequera and injured future president Ernesto Samper.

On 18 August the same year, Luis Carlos Galán, the Liberal Party's nominated presidential candidate and favourite for the election, was shot on stage during a rally.

[5] César Gaviria then became the party's main candidate; on 27 November Avianca Flight 203 carrying 107 people on board was bombed in an attempt to kill him.

[2] On 11 March 1990, the day of the primary elections, M-19 announced their disarmament and quickly emptied their weapons, burned their uniforms, and turned in their rifles and machine guns to be melted down before abandoning their hideouts.

[7] After taking over Galán’s campaign, Gaviria secured a prominent 59.9% majority in the primary election, making him the Liberal party’s clear choice.

He kept his apartment with barrels blocking the street, armed soldiers, sniffer dogs, and policemen checking all visitors with metal detectors.

This was a switch from prior elections where voters would walk into the voting booth with their candidate's ballot in hand, a practice long known to contribute to widespread vote-buying by local party bosses.

On 4 July 1991 a new constitution was ratified by the Constituent Assembly and combined almost two decades of political reform efforts by both presidents, parties, and citizens.

Notable changes included modifying it so that a party only needed to win one seat in either the house of Congress or have one of its candidates win at least 50,000 votes to gain legal recognition, designating that the Senate would be elected nationally instead of on the departmental level, and incorporating unseen guarantees of indigenous rights that encompassed two reserved seats in the Senate as well as representation in Congress.