The above situation created a growing divorce between society and politics in the 1970s and 1980s. Moreover, attempts to rationalise the state's bureaucracy and control of public spending unintentionally created further tensions between the technocratic and clientelist sectors, and further discredited the corrupt traditional political class. These events led to a serious crisis of political representation that profoundly affected the legitimacy of the state institutions and the means of political mediation in society. The result of this crisis was the constitutional reform of 1991, linked to peace processes with various guerrilla groups. The new Constitution recognised the ethnic, religious, cultural and regional pluralism of the country and tried to correct the most obvious vices of political life. But many of its reforms were frustrated or limited by subsequent legislation and the reality of political culture. The crisis was further complicated because the new Constitution’s decentralising measures and popular election of mayors and governors dislocated the political mechanisms through which the traditional parties mediated between the localities, the regions and the central state, without creating new mechanisms of political cohesion.
Meanwhile, the contours of violence were being transformed as the guerrillas began to expand from the peripheral areas towards richer areas more integrated into national economic and political structures. The guerrillas' increasing use of extortion and kidnapping as a means of finance started to alter society's perception of the conflict. From this stemmed the development of the paramilitary forces and a certain degree of public sympathy for the use of authoritarian solutions.
Furthermore, drug trafficking activities increased from the end of the 1970s. By the 1990s a significant growth in coca production took place because of the decline of plantations in Bolivia and Peru. Illicit crops found ideal conditions in the peripheral areas of colonisation where there was a low level of state presence and a social base in the form of the colonos (campesino settlers). Powerful drug cartels developed, particularly in Medellín and Cali, and launched a war against the state in the 1980s and 1990s. These were eventually defeated in the mid-1990s by the Colombian government with the military support of the United States. However the cartels divided into smaller groups. The US intensified its focus on Colombian drugs during the Clinton administration with the implementation of Plan Colombia from 1999.
The drug-traffickers, who slowly became landowners, contributed to the creation of paramilitary groups. In Puerto Boyacá in 1982 landowners, politicians, military personnel, ranchers, businessmen and a large oil-company formed the group Death to Kidnappers (MAS), in response to guerrilla kidnappings. The phenomenon began to extend across the country, particularly after 1984: other groups appeared such as the Campesino Self-Defence groups of Córdoba and Urabá (ACCU), founded by Carlos and Fidel Castaño, former members of MAS. In 1997, under the leadership of the Carlos Castaño, the United Self-Defence Forces of Colombia (AUC) was formed as an umbrella group for paramilitaries from across the country. At present some of these groups are negotiating their demobilisation with the government of Álvaro Uribe Vélez.
The expansion of illicit crops has also led to the transformation of the relationship between the guerrillas and drug trafficking. Some argue that the violence after 1980 represents a fundamental rupture with previous violence. To begin with the FARC dedicated itself to regulating relations amongst the campesino coca growers and with the drug traffickers, but gradually became more involved in levying tax on the crops, and later controlling the production and trafficking of coca. The income derived from illicit crops increased the FARC’s autonomy, which no longer depended on its integration into the rural communities. This has given greater emphasis to the military dimension of the conflict and increased the FARC's offensive and recruiting capacity.
At the same time, the penetration of drug-trafficking in Colombian society has contributed to widespread corruption and the delegitimisation of the political class. This reached its peak in 1994 when President Samper was accused of receiving money from the Cali cartel during his election campaign. The infiltration of the drug trade further deepened the fragmentation and privatisation of state power and the crisis of legitimacy of the political regime, and led to the blurring of boundaries between political violence and criminal activities such as extortion or bribery. In this context, the conflict ceased to have an exclusively political rationale and instead combined political and military objectives with economic and social goals; individual initiatives with collective actions; and struggles at a national level with conflicts of a regional and local character. Through this the violence has permeated the fabric of Colombian society, becoming the mechanism for the resolution of private and collective conflicts in the absence of the state.