AbstractThe imposition and lifting of COVID‐19 lockdown orders were among the most heatedly debated policies during the pandemic. Credible empirical evaluations of the effects of reopening policies are difficult because policymakers often explicitly linked sustained reductions in COVID‐19 cases to the lifting of lockdown orders. This hardwired policy endogeneity creates challenges in isolating the causal effects of lifting of lockdown orders on social mobility and public health. To overcome simultaneity bias, we exploit a natural experiment generated by the Wisconsin Supreme Court when it abolished Wisconsin's “Safer at Home” order on separation‐of‐powers grounds. We capitalize on this sudden, dramatic, and largely unanticipated termination of a statewide lockdown order to estimate its effect—relative to a more gradual scaling back of restrictions—on social mobility and COVID‐19 case growth. First, using anonymized smartphone data from SafeGraph and a synthetic control design, we find that termination of COVID‐related restrictions had small and short‐lived negative impacts on social distancing. Then, using data on case and mortality rates, we find no evidence that the Wisconsin Supreme Court decision impacted COVID‐19 growth up to a month following the repeal. These findings suggest that in the absence of carrying new information, sudden lockdown repeals may generate smaller behavioral responses than policymakers anticipate.