NCLC urged the Ninth Circuit to reject its “federal defendant rule” which bars parties from intervening on the federal government’s behalf to defend against alleged violations of the National Environmental Policy Act (NEPA). In this case, the Wilderness Society is challenging the U.S. Forest Service’s designation of 1,000 miles of roads and trails in Idaho for motorized recreational use. In its brief, NCLC argued that the brightline federal defendant rule is inconsistent with Rule 24 of the Federal Rules of Civil Procedure, which directs courts to consider how a case may affect a potential intervenor's interests before deciding whether to grant an intervention. NCLC also argued that the federal defendant rule is inconsistent with how the Ninth Circuit handles intervention motions under other environmental statutes. NCLC explained that businesses have significant interests that justify intervention in NEPA cases, and warned that the federal defendant rule encourages forum shopping by NEPA plaintiffs.