Catalan nationalism was labeled just one decade ago as a non-secessionist movement (Guibernau, 2004) its moderate character played an important role during the Transition period in Spain and the Spanish minority governments (both PSOE and PP). However Catalan regionalism saw a dramatic change during the last years and nowadays is self-defined as a pro-secessionist movement with a regional coalition Government (former regionalists plus secessionists) claiming the right to exercise self-determination. This paper analyzes the shift experienced by Catalan nationalism during the last ten years in three crucial dimensions for political unity: common way of life, nationhood and political participation (Kymlicka, 2002). I argue that these dimensions suffered a transformation in legitimating Catalan territorial demands. The failure in accommodating Catalan demands in Spain through a new Statute of autonomy is argued to be a “critical juncture” for the movement legitimizing a renewal of internal self-determination discourse towards an external self-determination position (Seymour, 2007). The European dimension is argued to play a crucial role in these changes in two different ways. First, as a third pole concerning Kimlicka’s dimensions allowing a certain bypass of the Spanish/Catalan debate especially in terms of citizenship and nationhood definition, but also as a democratic approach to the political conflict. Second, it has been used as a strategy and window of opportunity for further negotiations and as a third political arena for political actors (Parties, Social movements and Institutions).