Challenging the Liberal International Order: Evidence from the Parliamentary Assembly of the Council of Europe

International organizations promoting the Liberal International Order (LIO) have become increasingly contested by some of their own members that do not abide by liberal norms. Yet our knowledge about how these illiberal actors might influence the decision-making process within LIO international organizations remains limited. We compare illiberal regimes and illiberal parties from liberal regimes and argue that the later are the most serious challengers to LIO organizations. To provide evidence for our claims, we study roll call votes in the Parliamentary Assembly of the Council of Europe (PACE), one of the most powerful international parliaments to date and committed to promoting liberal values. Leveraging an original dataset recording more than 400,000 individual votes cast in PACE decisions, we find that illiberal opposition parties operating in liberal democratic countries most often challenge in PACE votes. Illiberal government parties, whether heading liberal or illiberal regimes, are somewhat less opposed to policy proposals, and their voting behavior does not significantly differ from each other. Contestation occurs predominately at the early stages of the parliamentary process but still is more common among illiberal parties in votes on final texts than among liberal parties. Our study has implications for the potential threat of emerging illiberal actors to international liberal institutions and organizations.