The concept of “animus” has taken center stage in high-stakes constitutional rights adjudication. Both in major equal protection cases and, more recently, in litigation over President Trump’s immigration bans and religion-based denials of commercial services to lesbians and gays, animus has emerged as a favored doctrinal tool of courts committed to protecting individual rights against majoritarian oppression. Despite—or perhaps because of—its prominence, the animus concept has remained controversial. Scholars have remarked on the difficulty of uncovering animus, its tendency to inflame the culture wars, and its potential to distract attention from other doctrinal paths that might be viewed as more promising for emerging social groups. At the same time, other scholars have attempted to create a workable animus doctrine from the Supreme Court’s under-theorized applications of the concept in well-known cases such as Romer v. Evans and City of Cleburne v. Cleburne Living Center.

This Article considers the arguments made by both the critics and defenders of the animus concept. After recounting the concept’s rise to prominence and scholars’ responses to that rise, it presents an approach to animus that both fits the Court’s analyses of the issue and harmonizes it with its approach to a closely related doctrine: discriminatory intent. This proffered approach answers the critics by explaining how courts can competently detect animus while mitigating the worst effects of an animus finding on public discourse on deeply contested concepts, and by suggesting how animus doctrine can benefit equal protection law more generally. That approach also fills in holes left by other scholars’ constructions of animus doctrine and refocuses animus away from mistaken directions implied by some of those constructions.

This Article then proceeds to contextualize animus within the broader sweep of American constitutional law by exploring the parallels between the animus concept and the nineteenth-century idea of class legislation. For over a century, the class legislation idea provided the prime organizing principle for state, and later, federal, courts’ enforcement of equality rights under both state constitutions and the U.S. Constitution. By connecting that older idea with modern animus doctrine, this Article aspires both to provide a stable doctrinal grounding for the animus concept, and, in turn, to secure modern equal protection law on a firmer, more historically legitimate, foundation.

This Article concludes by speculating more generally about the nature of constitutional rights adjudication. In particular, it considers whether such adjudication can ever hope to fully avoid the critique, leveled against the animus concept, that it necessarily involves name-calling that embitters the losing side and makes long-term social accommodation more difficult. This Article suggests that this unfortunate dynamic may often be inevitable, rather than simply a result of courts’ use of animus-based reasoning.