Who Participated in the ACA? Gains in Insurance Coverage by Political Partisanship

Context: The authors examined whether participation in the Affordable Care Act (ACA) differed by political partisanship. Answering this question is important for understanding how contentious elite-level decision making and discourse may affect policy uptake, and the ability of the ACA to create a constituency of beneficiaries invested in its support. Methods: The authors combined county-and individual-level data on health insurance gains, political partisanship, and variation in the ACA's implementation to test whether Democratic areas and individuals are more likely to gain health insurance after implementation of the ACA. Findings: While there was some evidence that Democrats experienced larger insurance gains than Republicans, the major partisan divide was in how insurance was obtained: Democrats were more likely than Republicans to enroll in private marketplace plans, but there were no partisan differences in uptake among those gaining insurance via the Medicaid expansions. Conclusions: These results provide some important context for the well-known and persistent partisan divide in support for the ACA, an attitudinal divide whose reflection in program participation appears conditional on the salience of different aspects of the ACA.