The Alaska Department of Fish and Game announced a program to kill wolves from aircraft in an attempt to increase the amount of moose in the interior region of the State of Alaska. Most of the wolves were located on federal land. The U.S. Department of the Interior (Department) (defendant) failed to prepare an environmental impact statement (EIS) for the program before authorizing it. The Defenders of Wildlife and other environmental and wildlife-preservation organizations (plaintiffs) filed a complaint against the secretary of the interior (secretary) and other Department officials (defendants), seeking declaratory and injunctive relief. The plaintiffs’ complaint alleged that the wolf hunt would disrupt the interior region’s ecology by interfering with the natural-selection process. The complaint also stated that the Federal Land Policy and Management Act (Act), 43 U.S.C. §§ 1701 et seq., required the secretary to evaluate whether meeting the Act’s environmental objectives required federal intervention to prevent the killing of wildlife. The Act gave state wildlife-management authority to the states and also permitted, but did not require, the secretary to supersede a state wildlife-management program after consulting with state authorities. The district court issued a temporary restraining order requiring the defendants to take all necessary steps to end the wolf-hunt program on federal land. The defendants appealed.