The Liberal and the Conservative parties agreed to alternate in the exercise of government power by presenting a joint National Front candidate to each election and restricting the participation of other political movements.
The initial power-sharing agreement was effective until 1974; nonetheless, with modifications, the Liberal–Conservative bipartisan system lasted until 1990.The sixteen-year extension of the bipartisan power-sharing agreement permitted the Liberal and Conservative élites to consolidate their socioeconomic control of Colombian society, and to strengthen the military to suppress political reform and radical politics proposing alternative forms of government for Colombia. The plan promoted industrial farming that would produce great yields of agricultural and animal products for worldwide exportation, while the Colombian government would provide subsidies to large-scale private farms.In 1961, a guerrilla leader and long-time PCC organizer named Manuel Marulanda Vélez declared an independent "Republic of Marquetalia".The Lleras government attempted unsuccessfully to attack the communities to drive out the guerrillas, due to fears that "a Cuban-style revolutionary situation might develop".During the 1960s, the Colombian government effected a policy of Accelerated Economic Development (AED), the agribusiness plan of Lauchlin Currie, a Canadian-born U. The AED policy came at the expense of the small-scale family farms that only yielded food supplies for local consumption.
Based on a legalistic interpretation of what constituted "efficient use" of the land, thousands of peasants were forcefully evicted from their farms and migrated to the cities, where they became part of the industrial labor pool.
In 1961, the dispossession of farmland had produced 40,000 landless families and by 1969 their numbers amounted to 400,000 throughout Colombia.
The AED policy increased the concentration of land ownership among cattle ranchers and urban industrialists, whose businesses expanded their profits as a result of reductions in the cost of labor wages after the influx of thousands of displaced peasants into the cities.
After the failed attacks, several army outposts were set up in the area.
In October 1959, the United States sent a "Special Survey Team" composed of counterinsurgency experts to investigate Colombia's internal security situation.
Among other policy recommendations the US team advised that "to shield the interests of both Colombian and US authorities against 'interventionist' charges any special aid given for internal security was to be sterile and covert in nature".