While they were long the exclusive preserve of representatives of nation states, international organizations (IOs) nowadays offer institutional access to a multitude of transnational actors (TNAs).What are the factors that have shaped this transformation towards a broader representation of NGOs, civil society groups, or multinational corporations? In this paper, we argue that domestic political systems are central to explaining patterns in TNA access. Theoretically, we develop different expectations on how the characteristics of the democratic clubs within IOs affect the openness. Empirically, the paper combines a statistical analysis of 50 IOs with a case study of the OSCE, an IO that has experienced significant changes in terms of domestic democratization and TNA access. We find that IOs with a large share of democratic members are more open to TNA representation, and that democratic transitions after 1989 are a prominent source of the openness revolution in global governance.
