Informal International Orders: The Social Structure and Purpose(s) of IIGO Member States

What makes informal intergovernmental organisations (IIGOs) hang together are their members' shared expectations about the organisation's purpose. Current research equates these expectations with the issue area(s) in which IIGOs operate, their issue scope, or the functions they perform. In doing so, it treats IIGOs as problem-solving instruments and disregards that they constitute social groups with distinct social purposes. While some IIGOs, like the G7, are composed mainly of liberal states, others, such as the BRICS+, mainly consist of illiberal states. Still others, e.g., the G20, bring together both groups. Building on this initial observation, this paper explores the social structures of IIGO member states and the purposes they pursue by acting through IIGOs. To this end, it conducts a network analysis of 545 IIGOs based on their membership and explains relevant social cliques using multivariate regression analysis. The network analysis shows that, through their membership in IIGOs, states have created an almost complete network that, however, varies significantly in terms of each state's weighted degree centrality. These differences can mainly be explained by the normative underpinnings of IIGO member states (liberal vs. illiberal purposes) and by their regional proximity. Based on these findings, the paper provides a building block for linking IIGO research to debates about social purpose, the role of liberal and illiberal states in international organisations, as well as international orders, and identifies directions for future research.