This paper will study the relation the armed activity of the terrorist group ETA and the evolution of the Basque public opinion in relation with the legitimacy of the use of violence for political motivation. The proposed article will assess the variation in the perceptions about violence among Basques using the series of the collection of opinion research studies Euskobarometer and will analyse the variation of the support to ETA with the intensity of the activity analysing the evolution and transformation in the forty years that have followed the death of Franco and the introduction of democracy in Spain.
