Master Supreme Court upheld the Clean Air Act’s delegation to EPA under the intelligible principle test and held EPA may not consider costs when setting NAAQS. with this comprehensive case brief.
Whitman v. American Trucking Associations, Inc. is a cornerstone of modern administrative and constitutional law on the nondelegation doctrine. The Supreme Court, in an opinion by Justice Scalia, reaffirmed that Congress can delegate broad policy-making discretion to agencies so long as it supplies an intelligible principle to guide and cabin that discretion. In doing so, the Court preserved a central mechanism of the modern regulatory state while also articulating limits: if a statute truly lacked a controlling standard, courts could not salvage it by allowing an agency to craft one post hoc.
The case also resolved an important interpretive question under the Clean Air Act (CAA): the Environmental Protection Agency (EPA) may not consider implementation costs when setting National Ambient Air Quality Standards (NAAQS) under §109(b)(1). And it addressed how revised ozone standards must be implemented under the CAA’s structure. For law students, Whitman both marks the high-water line for the permissibility of broad delegations and foreshadows debates over the scope of agency power, including later disputes about cost consideration and the separation-of-powers constraints on the administrative state.
531 U.S. 457 (2001)
Acting under §109 of the Clean Air Act (CAA), EPA in 1997 revised the NAAQS for ozone and particulate matter to more stringent levels. For ozone, EPA moved from a 1-hour to an 8-hour standard (0.08 ppm), and for particulate matter, it introduced standards for fine particles (PM2.5). Industry groups, including the American Trucking Associations, and several states petitioned for review in the D.C. Circuit. They argued, among other things, that §109(b)(1) unconstitutionally delegated legislative power because it supplied no determinate principle to guide EPA in choosing the precise level of air quality needed to protect public health; that EPA was required (or at least permitted) to consider costs when setting NAAQS; and that EPA’s approach to implementing the revised ozone standard improperly bypassed the more specific provisions governing ozone nonattainment in Part D, Subpart 2 of Title I of the CAA. The D.C. Circuit held that §109(b)(1) as construed by EPA amounted to an unconstitutional delegation unless the agency could adopt a limiting construction, and it remanded. It also held that EPA could not consider costs in setting NAAQS, and it questioned EPA’s implementation approach to ozone. The Supreme Court granted certiorari.
Does §109(b)(1) of the Clean Air Act unconstitutionally delegate legislative power to EPA by failing to provide an intelligible principle for setting NAAQS? May EPA consider implementation costs when setting NAAQS under §109(b)(1)? And how must EPA implement revised ozone NAAQS under the CAA’s Subpart 1 and Subpart 2 framework?
Under the nondelegation doctrine, Congress may delegate decision-making authority to an agency if it provides an intelligible principle to guide and limit the agency’s discretion. Courts may not cure an unconstitutional delegation by permitting an agency to craft the missing standard; if a statute lacks an intelligible principle, it must be struck down. Under CAA §109(b)(1), EPA must set NAAQS at levels “requisite to protect the public health” with “an adequate margin of safety,” which does not allow consideration of implementation costs. Specific statutory provisions control more general ones; EPA’s implementation of revised ozone standards must conform to the CAA’s specific ozone nonattainment scheme in Subpart 2.
1) The CAA’s directive to set NAAQS at levels “requisite to protect the public health” with an “adequate margin of safety” supplies an intelligible principle and does not constitute an unconstitutional delegation. 2) EPA may not consider costs in setting NAAQS under §109(b)(1). 3) EPA’s implementation of the revised ozone NAAQS must adhere to the specific framework of Subpart 2; the matter was remanded for proceedings consistent with that interpretation.
Nondelegation. The Court emphasized that it has invalidated statutes on nondelegation grounds only twice (both in 1935) and has since upheld delegations with broad formulations such as the “public interest” or “just and reasonable” standards. Section 109(b)(1)’s language, requiring standards “requisite to protect the public health” with an “adequate margin of safety,” sufficiently constrains EPA: “requisite” means no more than necessary to protect public health, and the margin of safety addresses uncertainties affecting sensitive populations. That is a workable standard that meaningfully cabins discretion. The D.C. Circuit erred in suggesting that EPA could repair any unconstitutional delegation by announcing a limiting construction; if Congress had failed to provide a standard, a court would have to invalidate the statute, not invite the agency to legislate one. Because §109(b)(1) itself contains an intelligible principle, there is no constitutional defect. Costs. The Court read §109(b)(1) to focus exclusively on public health. The statutory text’s use of “requisite” and the phrase “to protect the public health”—along with the Act’s structure, which elsewhere expressly authorizes cost considerations—unambiguously bars EPA from considering implementation costs when setting the level of NAAQS. Congress knew how to require cost-benefit balancing in other CAA programs; its omission in §109(b)(1) is dispositive. Thus, the D.C. Circuit’s rejection of cost consideration was affirmed. Ozone implementation. Addressing how to implement the revised ozone standard, the Court concluded that the CAA’s more specific Subpart 2 (which sets out an ozone-specific classification and attainment scheme) cannot be displaced by the general provisions in Subpart 1. The specific governs the general. EPA therefore could not proceed as though Subpart 2 were inapplicable to the revised ozone NAAQS. The Court remanded for further proceedings to align implementation with the statute’s structure and to address unresolved issues. Concurrences. Justice Thomas concurred, questioning whether the intelligible principle test is too permissive and suggesting willingness to revisit the doctrine. Justice Stevens (joined by Justice Souter) concurred in part, positing that agencies do exercise delegated legislative power but that such delegation here remained constitutionally permissible. Justice Breyer concurred in part, agreeing that costs are not considered under §109(b)(1) but noting that feasibility and background risk considerations can sometimes inform scientific judgments.
Whitman is the leading modern affirmation of the intelligible principle test and demonstrates how generous the Court has been in upholding broad delegations. It anchors the proposition that Congress may set general policy goals and entrust agencies with substantial discretion, provided a guiding standard exists. For administrative law, Whitman is routinely cited for two propositions: (1) the Clean Air Act’s health-based NAAQS contain an adequate intelligible principle, and (2) EPA may not consider costs when setting NAAQS under §109(b)(1). The decision also underscores separation-of-powers boundaries by rejecting the idea that agencies or courts can retroactively supply missing statutory standards. For law students studying nondelegation, Whitman marks the status quo against which later debates unfold. The concurrences hint at possible tightening of the doctrine, and subsequent cases developed adjacent constraints (such as the major questions doctrine) to police broad agency action. But as to nondelegation itself, Whitman remains a touchstone: it both preserves congressional flexibility to rely on agency expertise and clarifies that statutory text and structure—not post hoc agency rationales—must supply the governing principle.
The intelligible principle test asks whether Congress has provided a sufficiently clear standard to guide and constrain an agency’s discretion. In Whitman, the Court held that §109(b)(1)’s directive to set standards “requisite to protect the public health” with an “adequate margin of safety” adequately cabins EPA’s discretion, much like other broad but upheld standards such as “public interest” or “just and reasonable.”
No. The Court held that §109(b)(1) unambiguously forbids consideration of costs. The focus is strictly on public health protection. The Act’s structure confirms this: where Congress wanted costs considered, it said so explicitly in other programs, but not in §109(b)(1).
Because courts cannot cure an unconstitutional delegation by inviting an agency to supply the missing standard. If a statute truly lacks an intelligible principle, the remedy is to invalidate the delegation—not to let the agency legislate a new standard. Here, however, the Court found §109(b)(1) already contained an intelligible principle.
The Court concluded that the CAA’s ozone-specific Subpart 2, which sets classification and attainment requirements, governs and cannot be displaced by the general provisions in Subpart 1. EPA must implement revised ozone NAAQS in a manner consistent with Subpart 2; the case was remanded to align implementation with that framework.
Justice Thomas questioned whether the intelligible principle test is too permissive and signaled openness to revisiting it. Justice Stevens (joined by Souter) acknowledged that agencies exercise delegated legislative power but found the delegation here permissible. These concurrences left the door open to future tightening of the doctrine, even as the majority reaffirmed its lenient application.
Whitman reaffirms a permissive nondelegation standard while emphasizing that statutory text controls. Later cases developed the major questions doctrine to require clearer congressional authorization for decisions of vast economic and political significance. Whitman’s focus on statutory clarity and limits provides an interpretive backdrop for these later developments.
Whitman v. American Trucking solidifies the intelligible principle as the governing measure of permissible statutory delegation and confirms the durability of broad congressional delegations to administrative agencies. By holding that the Clean Air Act itself furnishes sufficient guidance—while refusing to let agencies invent limiting standards to rescue a defective statute—the Court both preserves agency-administered governance and polices the constitutional boundary.
The decision also draws a sharp line around health-based standard-setting by excluding costs from NAAQS determinations and clarifies the CAA’s internal structure for implementing revised ozone standards. For students, Whitman is essential reading to understand the modern nondelegation baseline, the limits on agency gap-filling, and the statutory interpretation principles that shape regulatory policymaking.