The Politics of Policy: The Initial Mass Political Effects of Medicaid Expansion in the States

Whether public policy affects electoral politics is an enduring question with an elusive answer. We identify the impact of the highly contested Patient Protection and Affordable Care Act (ACA) of 2010 by exploiting cross-state variation created by the 2012 Supreme Court decision in National Federation of Independent Business v. Sebelius. We compare changes in registration and turnout following the expansion of Medicaid in January of 2014 to show that counties in expansion states experience higher political participation compared to similar counties in nonexpansion states. Importantly, the increases we identify are concentrated in counties with the largest percentage of eligible beneficiaries. The effect on voter registration persists through the 2016 election, but an impact on voter turnout is only evident in 2014. Despite the partisan politics surrounding the ACA–a political environment that differs markedly from social programs producing policy feedbacks in the past—our evidence is broadly consistent with claims that social policy programs can produce some political impacts, at least in the short-term.