State of Wyoming v. United States 279 F.3d 1214 (10th Cir. 2002) Wild Elk in the National Elk Refuge (NER) in Wyoming were getting sick from a disease called brucellosis. Cattle ranchers worried that the elk might infect privately-owned cattle they come into contact with. For public health reasons, if cattle in an area are found to be infected with brucellosis, they can't be sold in interstate commerce, so the ranchers stood to lose a lot of money if they couldn't control the disease. An experimental brucellosis vaccine was available. Wyoming started vaccinating the wild elk that lived outside of the NER. Wyoming offered to vaccinate the wild elk on the NER to protect the cattle. The Fish and Wildlife Service (FWS) refused to allow the vaccination. FWS felt that the biosafety and efficacy of the vaccine was unproven. Wyoming sued to be allowed to vaccinate the elk. Wyoming claimed that the 10th Amendment gave them a sovereign right to manage wildlife within its borders. FWS claimed that the National Wildlife Refuge System Improvement Act of 1997 (NWRSI) gave them unlimited discretion to manage wildlife on the NER. The Trial Court found for the FWS. Wyoming appealed. The Trial Court found that that the 10th Amendment did not give Wyoming the right to manage elk on Federal lands. However, the Court suggested that Wyoming appeal the decision on the basis of whether the FWS decision was arbitrary and capricious. The Appellate Court remanded. The Appellate Court found that the 10th Amendment did not give Wyoming the right to manage elk on Federal lands. The Court found that NWRSI gave FWS the statutory authority to prevent the vaccination. However, the Court noted that under the Administrative Procedures Act (5 U.S.C. §706(2)(A)) FWS's decision could not be arbitrary and capricious. It must be based on a reasonable basis, and must take into account all of the factors they are required to take into account under NWRSI. NWRSI obligates FWS to promote "biological integrity, diversity, and environmental health." In this case, FWS had not prepared an Environmental Impact Statement (EIS) or had a complete record of their decision-making process. The Court remanded back to the Trial Court to determine if FWS's decision was arbitrary and capricious.