This article examines the determinants of multi-level states’ responses to the Covid-19 pandemic. It first maps out three categories of responses (non-coordination, coordination, centralisation) across 13 OECD countries over four time-periods in 2020. It then presents a theoretical framework drawn from public choice theory that specifies how these outcomes are shaped by how the pressures of the outbreak are mediated by institutional, sociological and party-political conditions. The findings of the fuzzy-set qualitative-comparative analysis (fsQCA) are that a necessary condition for non-coordination is the presence of a vertical party-political conflict, while for coordination it is the presence of shared-rule institutions. But this effect is asymmetric: shared-rule institutions do not preclude centralisation in countries with high population density and party-political consensus. These results yield extensions for how public choice theory can interpret the responses of multi-level states to future poly-crises, including those provoked by migration and climate-related disasters