Social Capital and Policy Compliance in a Polarized Democracy: A Necessary Condition Analysis of <scp>COVID</scp> Vaccination Rates Across US Counties

ABSTRACT Policy compliance, the extent to which citizens adhere to government policies, remains a central test of democratic governance, especially during the COVID‐19 pandemic in the United States. This study examines how distinct forms of social capital—relational, structural (bonding versus bridging), cognitive, and vertical linking—serve as critical preconditions for COVID‐19 vaccination uptake in 2021. Using necessary condition analysis (NCA), we uncover nuanced and context‐specific impacts of distinct social capital on policy compliance. NCA also identifies threshold levels of various social capital required to achieve specific vaccination outcomes, yielding actionable diagnostics for policymakers and administrators. Strategies to raise compliance must align with local social capital configurations, prioritizing bridging in Republican‐leaning counties and relational support and careful use of bridging in Democratic‐leaning counties. The study advances civil society research by pinpointing the civic preconditions under which democratic institutions can function effectively in a polarized environment.