Sometimes it’s possible to lose in name only. Consider, for example, Cato’s position in Kisor v. Wilkie, which the Supreme Court yesterday decided.

By a 5 – 4 vote, the Court upheld the Auer doctrine, or binding judicial deference to an agency’s interpretation of its own regulation. Only four Justices actually validated the Auer doctrine; Chief Justice Roberts provided the fifth vote solely out of respect for precedent. In a brief supporting the petitioner, Cato had argued that the Court should overturn Auer, so technically our position lost.

Nevertheless, the opinion of the Court “reinforced” and “expanded on” the doctrine’s limits. In Part II.B, Justice Kagan set forth several “markers” to guide lower courts regarding the boundaries of Auer deference. In practice, these limits gut the doctrine. As rightly observed by Justice Gorsuch, Auer emerges “maimed and enfeebled.” And because Auer deference has been rendered impotent, opponents of the doctrine effectively “won,” even though we officially “lost.”

So, how did the Court reduce Auer deference to a “paper tiger”? Justice Kagan set forth three big limitations.

The first is a requirement for courts to discern whether the regulatory text is ambiguous. While it might seem obvious that judges should ensure that a legal text is ambiguous before deferring to an agency’s interpretation, courts routinely skipped any meaningful textual analysis before assuming a deferential posture under the Auer framework. In an empirical study, I found that circuit courts failed to meaningfully examine the regulatory text about 35 percent of the time when they applied the Auer doctrine over a 15-year period. The upshot is that there’s a lot of room for courts to improve their craft when it comes to reviewing regulatory interpretations.

Kisor’s second limitation on Auer deference is a requirement that an agency’s regulatory interpretation reflect agency expertise. I expect that this “marker” on Auer’s domain will have the greatest influence on controversies over how to interpret an agency’s procedural regulations. After all, courts are more expert than agencies where due process is implicated. As a related aside, it bears noting that Kisor pertained to a dispute over the regulatory term “relevance” in an evidentiary context, which seemingly rests squarely in the wheelhouse of judicial expertise. Justice Kagan, however, did not draw this connection.

The third significant limitation on Auer was Kagan’s concession that binding deference is “rarely” warranted when an agency has changed its regulatory interpretation. This is huge; by itself, this call for interpretive consistency would have provided a mortal wound to the Auer doctrine. If a regulatory provision is of any consequence, and if it has existed for longer than one presidential administration, then there are vanishingly small odds that the agency’s interpretation has remained consistent. By holding that these interpretations would “rarely” achieve deference, the Court performs most of the work that goes into “enfeebling and maiming” the Auer doctrine.

Today’s unsung hero is the Solicitor General of the United States, Noel Francisco. Justice Kagan didn’t come up with these “markers” on her own. Rather, she borrowed them from the SG’s brief. As I previously explained, the SG’s unusual Kisor brief asked the Court to check the Auer doctrine, even though such a reform would diminish the government’s power. During oral arguments, Justice Kagan seemed concerned about the government’s anti-Auer argument, and she questioned in passing whether the petitioner and government were sufficiently adversarial. Given these apparent reservations, I’m a bit surprise she wholesale adopted the government’s arguments. In any case, the Solicitor General deserves kudos.