The Affordable Care Act (ACA) offers a window into modern American federalism—and modern American nationalism—in action. The ACA’s federalism is defined not by separation between state and federal, but rather by a national structure that invites state-led implementation. As it turns out, that structure was only a starting point for a remarkably dynamic and adaptive implementation process that has generated new state-federal arrangements. States move back and forth between different structural models vis-à-vis the federal government; internal state politics produce different state choices; states copy, compete, and cooperate with each other; and negotiation with federal counterparts is a near constant. These characteristics have endured through the change in presidential administration.

This Article presents the results of a study that tracked the details of the ACA’s federalism- related implementation from 2012 to 2017. Among the questions that motivated the project: Does the ACA actually effectuate “federalism,” and what are federalism’s key attributes when entwined with national statutory implementation? A federal law on the scale of the ACA presented a rare opportunity to investigate implementation from a statute’s very beginning and to provide the concrete detail often wanting in federalism scholarship.

The findings deconstruct assumptions about federalism made by theorists of all stripes, from formalist to modern. Federalism’s commonly invoked attributes—including autonomy, cooperation, experimentation, and variation—have not been dependent on any particular architecture of either state-federal separation or entanglement, even though theorists typically call on “federalism” to produce them. Instead, these attributes have been generated in ACA implementation across virtually every kind of governance model—that is, regardless whether states expand Medicaid; get waivers; or operate their own insurance exchanges or let the federal government do it for them. This makes it extraordinarily challenging to measure which structural arrangements are most “federalist,” especially because the various federalism attributes are not always present together.

The study also uncovers major theoretical difficulties when it comes to healthcare: Without a clear conception of the U.S. healthcare system’s goals, how can we know which structural arrangements serve it best, much less whether they are working? If healthcare federalism is a mechanism to produce particular policy outcomes, we should determine whether locating a particular facet of healthcare design in the states versus the federal government positively affects, for example, healthcare cost, access, or quality. If, instead, healthcare federalism serves structural aims regardless of policy ends—for instance, reserving power to states in the interest of sovereignty or checks and balances—we should examine whether it does in fact accomplish those goals, and we should justify why those goals outweigh the moral concerns that animate health policy. The ACA did not cause this conceptual confusion, but it retained and built on a fragmented healthcare landscape that already was riddled with structural and moral compromises.

This does not mean that federalism is an empty concept or that it does not exist in the ACA. Federalism scholars tend to argue for particular structural arrangements based on prior goals and values. The ACA’s architecture challenges whether any of these goals and values are unique to federalism or any particular expression of it. At the same time, the ACA’s implementation is clearly a story about state leverage, intrastate democracy, and state policy autonomy within, not apart from, a national statutory scheme. Its implementation illustrates how federalism is a proxy for many ideas and challenges us to ask what we are really fighting over, or seeking, when we invoke the concept in healthcare and beyond.

* Abbe R. Gluck is Professor of Law and Faculty Director of the Solomon Center for Health Law and Policy, Yale Law School; Nicole Huberfeld is Professor of Health Law, Ethics & Human Rights, Boston University School of Public Health, Professor of Law, Boston University School of Law.