Many argue that the frustrated implementation of the 2010 Affordable Care Act (ACA) stems from the unprecedented level of political polarization that has surrounded the legislation. This article draws attention to the law's “institutional DNA” as a source of political struggle in the 50 states. As designed, in the context of US federalism, the law fractured authority in ways that has opened up the possibility of contestation and confusion. The successful implementation of the ACA varies not only across state lines but also across the various components of the law. In particular, opponents of the ACA have experienced their greatest successes when they could take advantage of weak preexisting policy legacies, high levels of institutional fragmentation, and negative public sentiments. As argued in this article, the fragmented patterns of health care politics in the 50 states identified in previous research have largely persisted during the Trump administration. Moreover, while Republicans were unsuccessful at repealing the legislation, the administration has taken advantage of its structural deficiencies to further weaken the legislation's capacity to expand access to affordable, quality health insurance.