The decisions of the D.C. Circuit Court of Appeals in American Trucking Ass'n v. U.S. Environmental Protection Agency,¹ which remanded in part and vacated in part the U.S. Environmental Protection Agency's (EPA's) promulgation of revised national ambient air quality standards (NAAQS) for ozone and particulate matter (PM) under the federal Clean Air Act (CAA),² might have significant implications for the future of U.S. air quality law and policy. Some of these possible ramifications were explored in two earlier ELR articles by Professor Craig Oren.³ In addition to these direct impacts on CAA rulemakings, however, there has been considerable speculation about whether American Trucking signals a potential revival of the nondelegation doctrine in U.S. constitutional and administrative law.⁴ That development, in turn, might have far broader implications for the implementation of a panoply of environmental and other regulatory statutes by EPA and other federal agencies.

In his first article, Professor Oren wrote that the holding in American Trucking would be more consistent with a judicial remand under the arbitrary and capricious standard of the Administrative Procedure Act (APA),⁵ seeking a more precise agency explanation of the reasons underlying its regulatory decision.⁶ As a result, he appears to argue that fears about the broader implications of the D.C. Circuit's decisions in American Trucking are overstated.⁷ I agree with Professor Oren that if the court believed that EPA's explanation of the reasons underlying its regulation was inadequate,⁸ a remand under the APA would have been a far more conservative and preferable judicial approach. I am not so sanguine, however, that fears about the potential revival of the nondelegation doctrine are any less legitimate because of an approach the court could have adopted as opposed to the reasoning it actually endorsed.