The transfer of power in 1946 ignited tensions between the Liberal and Conservative parties, resulting in violent political conflict, particularly in rural areas. The loss of peace foreboded the return to competitive and exclusionary politics, similar to the situation preceding the War of a Thousand Days. In the 1940s and 1950s, however, violence and exclusion more than threatened the political system; they ruptured it. A democratically elected administration became repressive and dictatorial, which led to its overthrow by the sole military coup in the twentieth century. Only by having the reins of power taken from both of their hands did the traditional elites recognize that the most effective way to avoid interparty civil wars and possible military dictatorships was to join forces and restrain their competitive tendencies.

In 1946 Conservative Mariano Ospina Pérez assumed office and was faced with the difficult task of ruling from a minority position, as Liberals had received the majority of all presidential votes and continued to control Congress. Ospina tried to confront this situation by incorporating Liberals into a coalition government. Meanwhile, the level of political rivalry intensified in the countryside, where Conservatives pursued a course of violence in an attempt to consolidate power after sixteen years out of office. Liberals retaliated and, under Jorge Eliecer Gaitán's leadership, became highly mobilized in their demands that the Ospina government confront the social needs of the modernizing and urbanizing nation.

Gaitanism, the populist social movement led by Gaitán as a faction of the Liberal Party, increased dramatically between 1946 and 1948. Gaitán supported the democratic rather than the revolutionary path to reforms. By advocating the passage of more socially liberal policies, he appealed to the masses and he united urban workers and campesinos. As the movement grew, observers believed that Gaitán would be elected president, which may have happened had he lived to see the next election.

Liberal victories in the 1947 congressional elections demonstrated the party's strength among the electorate. Ospina became increasingly concerned with retaining
Conservative control and provoked Liberals further by resorting frequently to police enforcement of Conservative privileges in the rural areas. The Liberal
appointees in his government resigned in protest in March 1948.

The following month, the inevitable explosion occurred in the form of the most violent and destructive riot in the country's long history of conflict. On April 9, Gaitán
was assassinated at midday in the heart of Bogotá. An angry mob immediately seized and killed the assassin. In the ensuing riot, some 2,000 people were killed, and
a large portion of downtown Bogotá was destroyed. The Bogotazo, as the episode came to be called, was an expression of mass social frustration and grief by a
people who had lost the man who represented their only potential link to the decision-making process.

Although order was restored in Bogotá and Ospina remained in control, the tempo of rural violence quickened to a state of undeclared civil war known as la
violencia. La violencia claimed over 200,000 lives during the next eighteen years, with the bloodiest period occurring between 1948 and 1958. La violencia
spread throughout the country, especially in the Andes and the llanos (plains), sparing only the southernmost portion of Nariño and parts of the Caribbean coastal
area. An extremely complex phenomenon, la violencia was characterized by both partisan political rivalry and sheer rural banditry. The basic cause of this
protracted period of internal disorder, however, was the refusal of successive governments to accede to the people's demands for socioeconomic change.

After the Bogotazo, the Ospina government became more repressive. Ospina banned public meetings in March 1949 and fired all Liberal governors in May. In
November of that year, Ospina ordered the army to forcibly close Congress. Rural police forces heightened the effort against belligerents and Liberals, and
eventually all Liberals, from the ministerial to the local level, resigned their posts in protest.

In the 1949 presidential election, the Liberals refused to present a candidate; as a result, Laureano Gómez, the only Conservative candidate, took office in 1950. Gómez, who had opposed the Ospina administration for its initial complicity with the Liberals, was firmly in control of the party. As leader of the reactionary faction, he preferred authority, hierarchy, and order and was contemptuous of universal suffrage and majority rule. Gómez offered a program that combined traditional Conservative republicanism with the European corporatism of the time. A neofascist constitution drafted under his guidance in 1953 would have enhanced the autonomy of the presidency, expanded the powers of departmental governors, and strengthened the official role of the church in the political system.

Gómez acquired broad powers and curtailed civil liberties in an attempt to confront the mounting violence and the possibility that the Liberals might regain power.
Pro-labor laws passed in the 1930s were canceled by executive decree, independent labor unions were struck down, congressional elections were held without
opposition, the press was censored, courts were controlled by the executive, and freedom of worship was challenged as mobs attacked Protestant chapels. Gómez
directed his repression in particular against the Liberal opposition, which he branded as communist. At the height of the violence, the number of deaths reportedly
reached 1,000 per month.

Despite the relative prosperity of the economy--owing largely to expansion of the country's export markets and increased levels of foreign investment--Gómez lost
support because of protracted violence and his attacks on moderate Conservatives and on the military establishment. Because of illness, in November 1951 Gómez
allowed his first presidential designate, Roberto Urdaneta Arbeláez, to become acting president until Gómez could reassume the presidency. Although Urdaneta
followed Gómez's policies, he refused to dismiss General Gustavo Rojas Pinilla, whom Gómez suspected of conspiring against the government. When Gómez tried
to return to office in June 1953, a coalition consisting of moderate Conservatives who supported Ospina, the PL, and the armed forces deposed him and installed a
military government. They viewed such action as the only way to end the violence. Rojas Pinilla, who had led the coup d'état, assumed the presidency.