interconnected, as an overlapping constituency of formal international organisations, informal forums, and private actors shapes rules across almost every major policy area. This report examines what this growing complexity means for the robustness, effectiveness, and democratic quality of global governance. Drawing on 15 ENSURED case studies, the report relates empirical findings to academic debates on governance complexity and explores the quality of governance across five issue areas: trade and inequality, climate and biodiversity, global health, migration and human rights, and digitalisation. We find that complexity is neither inherently beneficial nor inherently harmful: instead, its effects depend on the architecture of governance complexes and the political alignment of powerful states. Hierarchical complexes with a recognisable centre that enjoy broad agreement among key states tend to stabilise governance, sustain output, and offer stronger mechanisms for democratic participation. Fragmented and politically divided complexes, by contrast, struggle with incoherent standards, selective implementation, and diffuse accountability. Building on these insights, the report highlights implications for political actors seeking to navigate and shape an increasingly dense global governance landscape.