Flexible firewalls: selective cooperation and strategic demarcation between centre-right and far-right parties in the EU

The success of far-right parties across Europe has sparked debate about whether centre-right parties maintain or abandon the cordon sanitaire against the far right. Moving beyond this binary, we conceptualise centre-right strategy in European Union politics as ‘flexible firewalls’, encompassing not only selective cooperation but also strategic demarcation. We develop an original explanatory framework accounting for this variation, based on two factors: issue-type and party acceptability. Divergent vote- and policy-seeking incentives explain why centre-right parties increasingly cooperate with far-right parties on policy issues (i.e., economic and social regulation) while maintaining or reinforcing firewalls on constitutive issues (e.g., European integration, rule of law). Moreover, the centre-right strategically (re)defines red lines for party acceptability, determining which far-right parties qualify as cooperation partners based on their positions on constitutive issues. We illustrate this argument empirically and demonstrate its explanatory power across the resulting four configurations, with evidence from the European Parliament.