The increasing influence of agency regulation in modern society makes effective execution of many laws dependent on proper functioning of the administrative state. Standing doctrine delineates the boundary between the powers of the executive and the judiciary, both of which have important functions in ensuring proper management of the administrative state. In Barnum Timber Co. v. U.S. Environmental Protection Agency, the Ninth Circuit probed this boundary, ultimately finding that the plaintiff had standing to sue EPA for the federal agency's allegedly arbitrary approval of a state agency's impaired waters list that it submitted to the EPA under the Clean Water Act. In this Note, I argue that the degree of judicial influence over agency action permitted by the Ninth Circuit's decision allows the judiciary to unduly interfere with the executive's ability to control the administrative state, which violates separation of powers. Limiting grants of standing for plaintiffs to sue federal agencies regulating state agencies while granting plaintiffs a private right of action to enforce their rights against the state agency directly causing the plaintiffs' injury would be less of an intrusion on the separation of powers and would promote more effective enforcement of the law.