How does a regulatory agency or a reviewing court deal with the multiple “enacted purposes” that may exist in a regulatory statute? In this Article it is argued that the problem of multiple purposes can be optimally dealt with by looking at these purposes as forming an optimization problem—minimization or maximization. This novel approach requires identifying, if possible, one purpose as the primary objective and then treating the other clearly stated purposes as constraints. Depending on the issue at hand, not all constraints will be relevant. However, the primary objective will always need to be considered. Once the primary objective and applicable constraints are identified, then the result can be used to define ambiguous statutory terms such as “in the public interest.” This optimization approach is utilized in evaluating the legal validity of the Surface Transportation Board’s new rule, Reciprocal Switching for Inadequate Service. The Board regulates the freight rail industry under the authority of the Staggers Rail Act of 1980. Reciprocal switching “is an arrangement that permits an industry served by a single rail carrier to access additional rail services through a competing line haul carrier.” The validity of the new rule is currently under review by the U.S. Court of Appeals for the Seventh Circuit. The Staggers Act provides that the Board may promulgate a rule implementing prescribed reciprocal switching if it is based on the authority derived from the term “in the public interest.” Unfortunately, when determining if it was acting “in the public interest” in promulgating its new rule, the Board did not adequately take into consideration all of the Act’s enacted purposes, including the primary objective of minimizing regulation. This is an unreasonable approach, an arbitrary and capricious act, and therefore the Seventh Circuit is duty bound to vacate it. Moreover, in a post-Chevron world, even if the Board were to revise its rule so it would be considered reasonable, a reviewing court could still find that its interpretation is not correct. This is where the applying of the optimization approach will be of most value, minimizing the risk that this will happen.