For more than seventy years, courts have deferred to reasonable agency interpretations of ambiguous regulations. The Auer principle, as it is now called, has attracted academic criticism and some skepticism within the Supreme Court. But the principle is entirely correct. In the absence of a clear congressional direction, courts should assume that because of their specialized competence, and their greater accountability, agencies are in the best position to decide on the meaning of ambiguous terms. The recent challenges to the Auer principle rest on fragile foundations, including an anachronistic understanding of the nature of interpretation, an overheated argument about the separation of powers, and an empirically unfounded and logically weak argument about agency incentives, which exemplifies what we call “the sign fallacy.”


Agencies issue countless regulations and, using the standard interpretive tools,1 courts sometimes find them ambiguous. What is the appropriate methodology for resolving such ambiguities?

There are two basic answers. The first, offered by long-standing law,2 is that the agency’s own interpretation generally prevails, with certain case-specific exceptions that we will discuss.3 The second,4 currently supported by a minority coalition on the Supreme Court (or perhaps only by Justice Clarence Thomas), is that judges must resolve the ambiguity without deference to the agency’s view.5

Sometimes long-standing law is right, and the best answer, by far, is the first. It reduces both the costs of decision and the costs of errors. It greatly simplifies the task of interpreting regulation; it also reflects a sensible understanding of institutional competence (as the second palpably does not). The resolution of ambiguities often involves complex issues of fact and value. Agencies, and not judges, should be settling those issues.

The argument in favor of independent judicial judgment reflects an emerging, large-scale distrust of the administrative state, even—in some quarters—a belief that it is constitutionally illegitimate.6 In our view, that belief is utterly baseless.7 But even if it is not, the appropriate response is hardly to say that judges, with their own institutional weaknesses and potential biases,8 should make the judgments that are entailed by resolving ambiguities in regulations. If taken seriously, general arguments from the separation of powers and general arguments about the constitutional illegitimacy of the administrative state would sweep far more broadly than the relatively modest problem of deference to agency interpretation of agency regulations. If taken seriously, those arguments would have radical implications for delegation, the combination of functions in agencies, and other fundamental features of the modern administrative state. There is a grave mismatch between the heavy constitutional
artillery and the idea that when some word in a regulation admits of more than one interpretation, courts should be able to make the choice.

Our basic goal here is to defend the first answer, known in the world of administrative law as the Auer principle, after a unanimous decision for the Court written by the late Justice Antonin Scalia in Auer v Robbins.9 In the process, we identify three reasons why a strand of the contemporary legal culture finds that principle jarring, in a sense even unbearable. The first involves anachronistic but influential understandings of what interpretation actually entails. Even in the aftermath of legal realism, some people believe that the interpretation of ambiguities calls for purely legal skills—as it plainly does not. Here we follow Scalia, Auer’s author, who insisted—at least until very late in his career—that interpretation necessarily includes consideration of policy consequences, and of the institutional roles that best serve to allocate responsibility for policy consequences.

The second reason involves the heavy constitutional artillery, applied in a context in which it does not belong and without regard to its far larger implications. In some ways, the issue of Auer deference appears to be a stalking horse for much larger game—namely, a wholesale critique of the administrative state. The constitutional critique of Auer rests on generalities about the separation of lawmaking from law execution and law interpretation. If applied consistently, those generalities would require declaring unconstitutional dozens of major federal agencies. The theory of the administrative state, for better or for worse, is that so long as separation of powers operates at the top level (Congress, presidency, judiciary), there is no general problem if the top-level institutions decide to create lower-level agencies that exercise combined functions. And in any event, it is quite clear that those agencies do not mingle or combine constitutional powers at all. So long as they act within and under a legislative grant of statutory authority, everything they do amounts to an exercise of “executive” power, including both the making and interpreting of rules, as Scalia emphasized for the Court as recently as 2013.10

The third reason involves an intuitively appealing, but wildly unrealistic, understanding of the incentive effects of Auer. Invocation of those incentive effects is a reflection of a pervasive error within the economic analysis of law, which is to identify the likely sign of an effect and then to declare victory, without examining its magnitude—without asking whether it is realistic to think that the effect will be significant. This error deserves its own name; we call it “the sign fallacy.”

As a matter of methodology, the three reasons share a similar defect. They invoke large abstractions—about the identification of meaning, about separation of powers, about agency incentives—to resolve a concrete puzzle for which such abstractions are either misplaced or unhelpful. The same defect can be found in many disputes about how judges should proceed; the Auer controversy is only one example.

  • 1. Because of our focus on Auer v Robbins, 519 US 452 (1997), we are bracketing here the question exactly what these are, but people are in broad agreement on them. There are disputes, of course, about (for example) the role of text, purpose, and avoidance of absurdity.
  • 2. See id at 461; Bowles v Seminole Rock & Sand Co, 325 US 410, 413–14 (1945).
  • 3. See Perez v Mortgage Bankers Association, 135 S Ct 1199, 1208 n 4 (2015) (listing qualifications to Auer deference).
  • 4. For the seminal article, with a host of original and ingenious arguments that appear to have inspired the attack on Auer, see generally John F. Manning, Constitutional Structure and Judicial Deference to Agency Interpretations of Agency Rules, 96 Colum L Rev 612 (1996).
  • 5. See Perez, 135 S Ct at 1213–25 (Thomas concurring in the judgment). There are actually two different versions of the alternative to Auer deference: either no deference, or so-called deference after Skidmore v Swift & Co, 323 US 134, 139–40 (1944). Justice Antonin Scalia seemingly preferred the former, see note 34 and accompanying text, while Professor John Manning argues for the latter, see Manning, 96 Colum L Rev at 618, 686–90 (cited in note 4). We discuss the Skidmore alternative at notes 86–89 and accompanying text.
  • 6. See Philip Hamburger, Is Administrative Law Unlawful? 12 (Chicago 2014). See also Cass R. Sunstein and Adrian Vermeule, The New Coke: On the Plural Aims of Administrative Law, 2015 S Ct Rev 41, 42–43.
  • 7. For a legal defense, see generally Adrian Vermeule, Law’s Abnegation: From Law’s Empire to the Administrative State (Harvard 2016). For a historical defense, see Jerry L. Mashaw, Creating the Administrative Constitution: The Lost One Hundred Years of American Administrative Law 312 (Yale 2012).
  • 8. See Thomas J. Miles and Cass R. Sunstein, Do Judges Make Regulatory Policy? An Empirical Investigation of Chevron, 73 U Chi L Rev 823, 825–26 (2006).
  • 9. 519 US 452 (1997).
  • 10. See text accompanying notes 53–55.