Taking enforcement on its own terms: EPA's heavy‐duty diesel engine litigation

The authors of Regulation by Litigation characterize the US Environmental Protection Agency (EPA)'s enforcement action against diesel engine manufacturers as an effort to achieve by litigation what the Agency was unable to achieve by regulation: immediate reductions in emissions of nitrogen oxides. By substituting litigation for rulemaking, the authors of the book argue, the Agency avoided political and judicial accountability and put itself on a suboptimal policy track. This comment argues that the diesel engine litigation may be better understood as what it purported to be, an enforcement action, not rulemaking in disguise. The authors' characterization of the litigation is questionable on at least two grounds. First, it fails to fully appreciate the distinct functions of enforcement and policymaking in a regulatory setting. The goal of enforcement is not primarily to make policy, but to enforce it – to punish violators, deter future violations, and mitigate harms caused by violations. That goal supplies the proper measure of the litigation's success. Second, in applying public choice analysis to create a story of agency circumvention of appropriate rulemaking procedures, the authors' account misses key features of how agency enforcement decisions are made – and were made in this litigation. This latter shortcoming raises broader questions about the difficulties of applying public choice analysis in complex institutional settings.