This paper discusses the socio-economic structural causes that favored the creation of drug cartels in Colombia. This paper argues that structural causes are often neglected from research on cartels and drug trafficking and the aim of this paper is to contribute to the understanding of how new policies can be achieved that are based on the comprehension of the deep socio-economic conditions which are a part of the very structures of Colombia and their relation to the cartels. This is done with a focus on the state and the social classes, and their development throughout the Colombian history since independence. The cartels are analyzed as criminal insurgencies in order to achieve a conceptual understanding of them. This paper concludes that the incomplete Colombian state formation, together with a great amount of marginalization of the lower social classes have been decisive factors in the creation of the criminal insurgencies and consequently, that we need to rethink the current policies on the war on drugs, since the policies in place have been rather unsuccessful in blocking the development of powerful cartels, not only in Colombia but Latin America in general.