ABSTRACT
Given the relatively conservative and marketized nature of U.S. health care reform, it remains unclear both why Republican resistance has been so intractable through much of the Affordable Care Act's (ACA's) tenure and why it has so suddenly receded into the background. This article seeks an explanatory mechanism to make sense of the ACA's changing historical fortunes, from enactment to the present. It argues that the Republican Party's "rules of reproduction," a concept of historical sociology, best explains why the ACA met with such vociferous resistance and why that resistance has given way to surprising progress on coverage. It begins with a consideration of marketized U.S. health care, as well as the ACA's quest for expanded coverage-not structural rearrangement-as the basis for progressive change. Following this, I explore the "rules of reproduction" to explain Republican political actors' relentless attacks on the law. The final section considers how the historically-contingent COVID-19 event has dovetailed with ACA entrenchment, effectively "flipping the script" on Republican rules, making anti-Obamacare maneuvers far less politically palatable. It is in this political space that reform advocates have been able to seize opportunity and broaden access.
