The Thermostatic Impact of Medicaid Expansion on United States Elections

• In Event: Health, Health Policy Design, and the Effects on Political Attitudes & Behavior

Abstract

In a democracy, politicians are punished when they deviate from the preferences of the citizens they represent. Public opinion for one, shifts thermostatically to punish the party in power. Yet, little is known about whether such thermostatic reactions translate into electoral behavior. Focusing on the 2010 Affordable Care Act, I show using zip code-level returns of national and state elections between 2008 and 2020 that Democratic candidates across the country were punished by voters in states that expanded Medicaid and those that did not. Additionally, I identify a local treatment effect using county border-pairs in expansion and non-expansion states. Initial results show that the expansion of Medicaid led to a decline of the Democratic presidential vote share in 2016 by 2 percentage points on average and 4 percentage points among Democratic Senate candidates who ran in expansion states. At the state level, the mean electoral loss among Democratic gubernatorial and state senate candidates was 9 and 6 percentage points respectively. Although Medicaid provides health insurance to low-income individuals, voters living in counties where real earnings per capita were below the median were just as likely to punish national Democratic candidates, in the magnitude of 1 and 4 percentage points. Overall, the findings suggest that while voters were able to exercise some degree of policy accountability, they also highlight the limits of interest-based explanations of policy support.

Author

• Dickson Su, Public Agenda