DISINTEGRATION is a research project run by Stefanie Walter (University of Zurich) and funded by an ERC Consolidator Grant. It examines the mass politics of disintegration and pays particular attention how other voters, elites and governments in other countries respond to voter-endorsed challenges to international institutions. PUBLIC OPINION (WP 1): When and how does one country’s mass-based disintegration experience encourage or deter demands for disintegration in other countries? DOMESTIC DISCOURSE (WP 2): How are the contagion effects of mass-based disintegration transmitted through domestic elites and domestic discourse? DISINTEGRATION NEGOTIATIONS (WP 3): How do an international institution’s other member states respond to one member state’s mass-based disintegration bid? THEORIZING DISINTEGRATION (WP 4): Building a theory of mass-based disintegration. DISINTEGRATION is a research project funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program grant agreement No 817582 (ERC Consolidator Grant DISINTEGRATION, 2019-2024) and the University of Zurich.