Section 264 “Inspection” Authority Encompasses Dog Microchip and Minimum-Age Import Requirements

Introduction

In U.S. Sportsmen's Alliance Found. v. CDC (6th Cir. Feb. 13, 2026), the Sixth Circuit affirmed the denial of a preliminary injunction sought by the United States Sportsmen's Alliance Foundation and individual plaintiffs (a hunter and a Canadian dog breeder). They challenged key portions of the CDC’s 2024 updates to the federal “Dog Rule,” which governs dog importation to prevent reintroduction of dog-transmitted rabies into the United States.

The challenged provisions required (1) microchipping of imported dogs and (2) a minimum age of six months for entry. Plaintiffs argued these requirements exceeded CDC statutory authority (principally under 42 U.S.C. § 264), implicated the major questions doctrine, conflicted with other statutes, and were arbitrary and capricious under the Administrative Procedure Act (APA).

Summary of the Opinion

The Sixth Circuit held the plaintiffs were unlikely to succeed on the merits of their claims that the CDC lacked statutory authority and that the rule was arbitrary and capricious. Because likelihood of success is a threshold preliminary-injunction factor, the court affirmed without reaching irreparable harm, balance of equities, or public interest.

On statutory authority, the court concluded that 42 U.S.C. § 264(a) likely authorizes the microchip and minimum-age requirements as (i) part of permissible “inspection” measures and/or (ii) permissible “other measures” to prevent introduction of communicable disease. On arbitrariness, it found the CDC offered a reasoned explanation tied to documented fraud and rabies-risk concerns.

Analysis

Precedents Cited

  • Wonderland Shopping Ctr. Venture Ltd. P'ship v. CDC Mortg. Cap., Inc., 274 F.3d 1085 (6th Cir. 2001); Kentucky v. United States ex rel. Hagel, 759 F.3d 588 (6th Cir. 2014)
    Role: Provided the appellate standard of review in preliminary-injunction appeals (law de novo, facts for clear error, remedial decision for abuse of discretion).
  • EOG Res., Inc. v. Lucky Land Mgmt., LLC, 134 F.4th 868 (6th Cir. 2025) (quoting Winter v. Nat. Res. Def. Council, Inc., 555 U.S. 7 (2008))
    Role: Framed the four-factor preliminary injunction test and emphasized the centrality of likelihood of success.
  • Wilson v. Williams, 961 F.3d 829 (6th Cir. 2020)
    Role: Supported the court’s choice to end the analysis once it found plaintiffs failed to show likelihood of success.
  • Loper Bright Enters. v. Raimondo, 603 U.S. 369 (2024)
    Role: Drove the court’s interpretive posture: courts must exercise independent judgment on agency statutory authority and may not defer to an agency’s legal conclusions; the court must use “traditional tools” to find the statute’s “single, best meaning.” This is the opinion’s most consequential doctrinal anchor.
  • Ohio Telecom Ass'n v. FCC, 150 F.4th 694 (6th Cir. 2025)
    Role: Applied Loper Bright Enters. v. Raimondo in-circuit: no deference on legal meaning, though an agency’s views can be considered for persuasive value given expertise.
  • Calcutt v. FDIC, 598 U.S. 623 (2023) (per curiam)
    Role: Addressed the “post hoc rationalization” concern; the Sixth Circuit rejected plaintiffs’ suggestion that “inspection” was newly invented on appeal, noting the CDC cited the inspection rationale repeatedly in the rulemaking record.
  • Kentucky v. EPA, 123 F.4th 447 (6th Cir. 2024), cert. denied, 145 S. Ct. 2847 (2025)
    Role: Supplied the court’s canon-like explanation of how statutory catchall language (“other measures”) following a list typically covers things similar to the list items—supporting reading § 264(a)’s “other measures” to include microchips and minimum age.
  • Ala. Ass'n of Realtors v. HHS, 594 U.S. 758 (2021) (per curiam)
    Role: Plaintiffs used it to argue § 264 authority is limited; the court distinguished it as involving an “attenuated” link (evictions → movement → infection), whereas the Dog Rule directly targets disease introduction through imported animals.
  • Biden v. Nebraska, 600 U.S. 477 (2023); Tiger Lily, LLC v. HUD, 5 F.4th 666 (6th Cir. 2021); Util. Air Regul. Grp. v. EPA, 573 U.S. 302 (2014); Biden v. Nebraska, 600 U.S. 477 (2023) (Barrett, J., concurring)
    Role: Framed and bounded the major questions doctrine. The court emphasized scale and novelty: the Dog Rule is narrow and affects a small slice of conduct, unlike sweeping loan forgiveness or an eviction moratorium. It further stressed that major questions is not a “magic-words doctrine” and that § 264(a) is sufficiently clear in context to authorize inspection-related conditions.
  • HUD v. Rucker, 535 U.S. 125 (2002); United States v. Callahan, 801 F.3d 606 (6th Cir. 2015)
    Role: Supported the court’s limited use of legislative history where statutory text is unambiguous.
  • Nat'l Ass'n of Home Builders v. Defs. of Wildlife, 551 U.S. 644 (2007); Simms v. NHTSA, 45 F.3d 999 (6th Cir. 1995) (quoting Citizens to Pres. Overton Park, Inc. v. Volpe, 401 U.S. 402 (1971), abrogated in part on other grounds by Califano v. Sanders, 430 U.S. 99 (1977))
    Role: Defined the deferential nature of arbitrary-and-capricious review and the prohibition on courts substituting their policy judgment for the agency’s.
  • Motor Vehicle Mfrs. Ass'n of the U.S., Inc. v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29 (1983) (quoting Burlington Truck Lines, Inc. v. United States, 371 U.S. 156 (1962)); FCC v. Prometheus Radio Project, 592 U.S. 414 (2021); Ky. Waterways All. v. Johnson, 540 F.3d 466 (6th Cir. 2008)
    Role: Supplied the governing “reasoned decisionmaking” framework: rational connection, consideration of important aspects, and plausibility.
  • Univ. of Cincinnati v. Heckler, 733 F.2d 1171 (6th Cir. 1984)
    Role: Supported the proposition that agencies may deploy overlapping prophylactic measures and that over-/under-inclusiveness does not itself establish arbitrariness.
  • New York v. Compagnie Generale Transatlantique, 107 U.S. (17 Otto) 59 (1883)
    Role: Rejected as inapt; it concerned state taxation and the Import-Export Clause, not federal public health authority under § 264.
  • In re Burke, 863 F.3d 521 (6th Cir. 2017) (quoting Kuhn v. Washtenaw Cnty., 709 F.3d 612 (6th Cir. 2013))
    Role: Waiver doctrine: arguments not raised in the opening brief are waived. The court used this to limit the challenge largely to the age and microchip requirements, not the DIF paperwork component.

Legal Reasoning

1) Post-Loper Bright statutory review: independent judicial judgment

A key methodological feature of the decision is its explicit reliance on Loper Bright Enters. v. Raimondo: the court did not treat the CDC’s interpretation as entitled to deference. Instead, it undertook its own reading of § 264(a) using traditional tools (text, context, and contemporaneous dictionary definitions), while allowing agency expertise to be persuasive only if warranted.

2) Reading 42 U.S.C. § 264(a): “inspection” and “other measures”

The court treated § 264(a) as providing two textual footholds:

  • “inspection”: Using early-20th-century dictionary definitions, the court construed inspection as “look[ing] into” an item to ascertain its “quality or condition.” Microchipping, in the court’s view, operationalizes inspection by reliably linking the dog physically presented at entry to the dog described in the paperwork—making inspection meaningful rather than easily defeated by identity fraud.
  • “other measures”: The court read the catchall to include measures similar in character to those listed (inspection, fumigation, disinfection, sanitation, pest extermination, destruction of animals/articles). Both microchipping and minimum age were characterized as disease-prevention measures tightly connected to identifying potentially rabid animals at the border.

On the minimum-age requirement, the CDC’s rationale—difficulty distinguishing rabies symptoms from normal very-young-puppy behavior and ensuring dogs are old enough for effective vaccination— made the measure, in the panel’s view, part of determining a dog’s condition and preventing uncertain-risk animals from entering.

3) Distinguishing the eviction moratorium line of cases

Plaintiffs attempted to analogize to Ala. Ass'n of Realtors v. HHS. The court distinguished the Dog Rule as directly tied to disease introduction at the border, unlike the moratorium’s attenuated causal chain. Rather than narrowing § 264(a), Ala. Ass'n of Realtors v. HHS was treated as illustrating that § 264 authority is strongest where measures directly identify and stop disease vectors.

4) Major questions doctrine: scale, novelty, and statutory clarity

The panel concluded the doctrine likely does not apply because the rule is comparatively modest in scope and economic/political significance. Even assuming heightened scrutiny, the court found adequate congressional authorization in § 264(a)’s inspection power and rulemaking authority to implement inspection-enabling conditions. It rejected any notion that Congress must specify microchips or “six months” explicitly, relying on the principle (citing Biden v. Nebraska (Barrett, J., concurring)) that major questions is not a “magic-words” requirement.

5) No separate statutory bar from 42 U.S.C. § 265 or the Animal Welfare Act

The court treated the rule as imposing conditions rather than a categorical “ban” under § 265. It also rejected the argument that the Animal Welfare Act’s treatment of certain dog importation contexts implied Congress meant to preclude CDC regulation of all other dog imports.

6) Arbitrary-and-capricious review: reasoned explanation, not perfect tailoring

Applying Motor Vehicle Mfrs. Ass'n of the U.S., Inc. v. State Farm Mut. Auto. Ins. Co. and FCC v. Prometheus Radio Project, the court found the CDC articulated a rational connection between record evidence (fraudulent paperwork enabling importation of rabid dogs; documented downstream costs and exposures) and the chosen measures (microchips to reduce identity fraud; age floor to improve screening and vaccine reliability).

The opinion emphasized restraint: under Univ. of Cincinnati v. Heckler, agencies may adopt overlapping prophylactic measures and need not solve the entire problem. The court also rejected the claim the CDC acted irrationally by regulating globally rather than only “high-risk” countries, crediting the agency’s finding that fraudsters route dogs through low-risk countries to evade controls and reiterating that courts do not invalidate rules merely for arguable over-/under-inclusiveness.

Impact

  • Concrete post-Loper Bright template for reviewing CDC quarantine authority: The decision is a worked example of independent statutory interpretation that still credits agency expertise where it supports, rather than defines, statutory meaning.
  • Broad understanding of “inspection” as operationally effective inspection: The microchip holding suggests agencies may require identifying information and prerequisites that make border inspections functional, not merely ceremonial.
  • “Other measures” supports pragmatic disease-prevention conditions at the border: By analogizing minimum age to measures aimed at assessing and mitigating risk before entry, the opinion strengthens CDC authority to adopt screening-oriented entry conditions for animals.
  • Major questions doctrine cabined in narrow public-health import controls: The panel signaled that targeted, long-familiar public health controls—especially at international borders—are less likely to trigger major-questions skepticism than sweeping domestic economic regulations.
  • Litigation positioning matters: The waiver discussion (re DIF paperwork) is a reminder that regulated parties must clearly preserve challenges to all components they intend to contest on appeal.

Complex Concepts Simplified

Preliminary injunction
A fast, temporary court order issued at the start of a case. To get it, plaintiffs must show, among other things, they are likely to win later on the merits. If they can’t show that, courts often deny the request without further analysis.
APA “in excess of statutory authority” (5 U.S.C. § 706(2)(C))
Courts set aside agency actions that go beyond what Congress authorized in the agency’s statute.
Post-Loper Bright review
Courts themselves decide what statutes mean; agencies do not receive controlling judicial deference on legal interpretations. An agency can still be persuasive, but it does not get the final say.
Arbitrary and capricious (5 U.S.C. § 706(2)(A))
A rule fails if the agency didn’t reasonably explain it, ignored important aspects of the problem, relied on improper factors, or contradicted the evidence. Courts do not require the “best” policy—only a rationally explained one.
Major questions doctrine
A principle that courts expect especially clear congressional authorization for agency actions of vast economic and political significance. The Sixth Circuit treated the Dog Rule as too modest to qualify and, in any event, sufficiently grounded in § 264(a).
Catchall provisions (“other measures”)
When a statute lists specific tools and then adds a broader phrase, the broad phrase is usually read to include similar kinds of tools, not unrelated ones—here used to support microchip and age requirements as border disease-prevention measures.

Conclusion

U.S. Sportsmen's Alliance Found. v. CDC reinforces that, under 42 U.S.C. § 264(a), the CDC likely may adopt import-entry conditions that make animal disease inspections effective—specifically, microchip identification and a six-month minimum age— and that such measures will generally survive arbitrary-and-capricious review when supported by a documented fraud-and-risk record and a reasoned explanation. The opinion also illustrates the Sixth Circuit’s post-Loper Bright Enters. v. Raimondo approach: independent statutory judgment paired with respect for agency expertise only where it persuasively supports, rather than dictates, the statute’s best reading.