State of Wyoming v. United States

After elk in Wyoming's National Elk Refuge (NER) became infected with brucellosis, a disease causing miscarriages that also threatened Wyoming's federally certified brucellosis-free cattle industry, Wyoming (plaintiff) sought Fish and Wildlife Service (FWS, defendant) approval to vaccinate elk within the NER, but the FWS denied the request citing insufficient safety and effectiveness data and then failed to issue any final determination for over a decade. Wyoming sued, invoking the National Wildlife Refuge System Improvement Act's savings clause (preserving state authority to manage wildlife within refuges) and the Administrative Procedure Act (APA); the district court dismissed, finding the Act gave FWS unlimited management discretion, and Wyoming appealed.