This paper analyzes the public expression of ideological antagonism as a discursive, interactional accomplishment within one of Spain’s most polarized contemporary issues: Catalan independence. Using Discursive Psychology, we analyze seven focus groups (n=49) with lay citizens holding different political stances on Catalan self-determination. Our analysis investigates how participants collaboratively assign blame for polarization and manage highly critical views of outgroups within a rhetorical stance of reasonableness. Through the mobilization of competing notions of national citizenship and democracy, participants argue for the (i)legitimacy of distinct national projects. We also examine how some participants, within this highly conflictual atmosphere, collectively legitimize and defend illiberal measures against ideological adversaries as a rational and reasonable course of action. Issues of nationhood and citizenship are negotiated through varied interpretative repertoires, enabling participants to contrast commonsense rationality with perceived biases of political antagonists. This study contributes to literature on citizenship and political polarization by emphasizing the interactional construction of polarized views, shifting focus from cognitive processes to the rhetorical enactment of ideological antagonism in everyday argumentation.