Rodrigo Lara was born during the critical years of bipartisan violence in a region in the south of Colombia. During his adolescence he witnessed the establishment of the Frente Nacional, and the country began to feel its consequences when political yearnings began to awaken in him. He oscillated between the ruling party and the dissidence of the Liberal Party, but he was always a strong defender of social policies, in the same way that he denounced patronage. He was Mayor, Councilman, Deputy, Senator and Minister of the Republic, taking an active part in important political, economic and administrative processes. Finally, in his last months of life, he was one of the first to speak of the entry of drug trafficking into politics, a phenomenon that the country was beginning to experience and that would be the catalyst for the crisis of the regime inherited from the Frente Nacional. To ask about Rodrigo's life is to question about Colombia's political history of the late twentieth century. It is to investigate the changes introduced by the National Front and the consequences of these in the political regime. But it is also to discuss the formation of dissidences of the Liberal Party, a process that necessarily nourishes the historical debate on the two-party system. In this order of ideas, from Lara's life experience, this work asks about the evolution in the dissidence formation of the political regime, within the Liberal Party and as a result of the practices introduced by the Frente Nacional. Starting with the reconstruction of Lara's political career and his participation in different dissidences,he aim is to show how the Frente Nacional introduced a series of changes in the political regime that necessarily affected the way in which the dissidence of the Liberal Party emerged and were characterized.