This study examines the debates on nationalism, terrorism and conflict resolution, and intends to identify, on the one hand, the reasons why and the instances in which nationalist discourses usurp the notions of political violence and present it as a legitimate option for opposing a State, and on the other, whether there exist circumstances where conflict resolution techniques and approaches can be useful in isolating terrorist discourses from the nationalist ones, without necessarily criminalising the latter. The study employs a critical and discourse analysis approach to explaining ethno-nationalist and terrorist phenomena, arguing that a contextualisation of the nationalist and terrorist objects of study is necessary in order to comprehensively analyse the relationship between the two, and the instances where the former gives rise to the latter. The purpose of the study is to develop a theoretical framework for the understanding of nationalism and terrorism as interconnected practices, and looks into ways in which conflict resolution can intervene and prevent the infusion of the two. In order to test this framework, the thesis examines the Basque conflict and discusses how the discriminatory practices of the Francoist dictatorship towards the Basques played a catalytic role in their acceptance of violence as a legitimate vehicle of pursuit of the nationalist aim of independence, and how the radicalisation of counter-terrorist practices after the democratic transition further distanced the civil society from both the State and the militant group. The study analyses the role of the Basque civil society, and how it became the primary actor in the transformation of the conflict by rejecting violent practices from both the State and ETA, while at the same time promoting a more civic aspect of the Basque nationalist discourse. This attitude allows the thesis to conclude that, contrary to theories of conflict resolution, the State can combat terrorism most effectively when it allies with civil society in the alteration of perceptions that perpetuate violence, but instead favour a strictly political approach to the pursuit of political objectives, like self-determination.