The United States federal government maintains a government-to-government relationship with federally recognized American Indian tribes and Alaska Native (AI/AN) entities. The “government-to-government” relationship is based in the U.S. Constitution, treaties, Federal statutes, court decisions, and Executive Branch policies, as well as moral and ethical considerations.

Source: https://tools.cdc.gov/api/embed/downloader/download.asp?m=403372&c=406284