In 2009, Ruby Pipeline, L.L.C. proposed to build a 678-mile pipeline from Wyoming to Oregon that would cross through the critical habitat of endangered species. The Federal Energy Regulatory Commission and the Fish and Wildlife Service worked with Ruby to design a Conservation Action Plan consisting of voluntary measures aimed at mitigating the effects of the pipeline on nine endangered fish species. Relying on the plan, federal agencies approved the pipeline project. Environmental groups challenged the agencies’ decision to rely on a voluntary conservation plan. In Center for Biological Diversity v. U.S. Bureau of Land Management, the U.S. Court of Appeals for the Ninth Circuit held that the agencies violated the Endangered Species Act because the Act requires enforceable rather than voluntary conservation plans. This Comment argues that the Ninth Circuit’s decision correctly clarifies the role that public-private conservation plans may play within the ESA in a way that will ensure the protection of endangered species.