Democracy’s crisis advantage seems conditional: evidence from excess mortality across island and non-island jurisdictions for the Covid-19 pandemic

Institutional advantages in crisis may be conditional on whether policies can be feasibly implemented. We test this using the Covid-19 pandemic, examining whether the associations of democracy and income inequality with outcomes vary across contexts with different implementation constraints. Using data from 193 jurisdictions, we link democracy (V-Dem Liberal Democracy Index) and income inequality (Gini coefficient) to age-standardised excess mortality (2020–2021) and GDP per-capita growth, comparing island and non-island settings. Democracy predicted lower excess mortality in island jurisdictions, but failed to do so in non-island jurisdictions, supported by a democracy–island interaction. In contrast, higher inequality predicted greater mortality and deeper economic contraction in non-islands, while democracy showed no consistent association with GDP trajectories. These findings suggest that institutional effects on crisis outcomes are context-dependent, with democracy conferring advantages when implementation constraints are lower, and inequality acting as a broader constraint on effective collective action.