Medicaid Expansion Through Ballot Initiatives Increased Medicaid Enrollment And Reduced Uninsurance Among Adults

Between 2019 and 2021, six states expanded Medicaid through voter-approved ballot initiatives, overcoming legislative opposition. We used 2016-23 data from the American Community Survey to compare health insurance coverage outcomes in these six ballot initiative states with those in ten nonexpansion states. We estimated stacked event study regression models to account for variation in expansion timing and control for socioeconomic differences. Overall, ballot initiative expansions increased Medicaid enrollment by 3.2 percentage points and decreased uninsurance by 2.2 percentage points among nonelderly adults two years after expansion. Among low-income adults, Medicaid coverage increased by 10.1 percentage points, and uninsurance fell by 6.2 percentage points. These findings show that Medicaid expansions enacted through ballot initiatives significantly increased coverage, even in politically resistant environments. However, sustaining these gains may be difficult amid ongoing state-level opposition and new federal mandates. As opportunities for future ballot-driven expansions narrow, this study highlights both the potential and the limitations of direct democracy in advancing health policy.