The Chickasaw Nation v. United States case in 2001 revolved around the issue of whether federal gambling excise and occupational taxes could be imposed on tribal governments operating bingo games, despite a statutory exemption for "any State or political subdivision thereof." The Chickasaw Nation argued that they should be included within this exemption as sovereign entities. However, the Supreme Court ruled against them in an unanimous decision stating that Congress did not explicitly include tribes within the tax exemption clause. Therefore, it was concluded that Indian tribes are subject to federal wagering taxes because they were not specifically exempted by law from such taxation. This ruling upheld the principle of interpreting waivers of tribal sovereignty narrowly and reinforced Congressional authority over Native American affairs.

In the dissenting opinion for Chickasaw Nation v. United States, Justice Ginsburg disagreed with the majority's interpretation of ambiguous statutory language regarding taxation of tribal gaming revenues. She argued that in cases where Congress' intent is unclear, courts should interpret ambiguities in favor of Native American tribes due to their sovereign status and unique relationship with the federal government. In this case, she believed that ambiguity existed because different sections of the statute could be interpreted differently - one section suggested that tribes were exempt from taxes while another implied they were not. Therefore, she would have ruled in favor of tax exemption for Chickasaw Nation.