Following passage of the 1972 Appropriations Act, the Bureau of Indian Affairs (BIA) reviewed the 1958 Bylaws of the Delaware Tribe of Indians. It recommended that the tribe adopt membership criteria to comply with the distribution requirements of the Act. In a General Council meeting, the Delaware Tribe amended its bylaws to include such criteria, and the BIA approved the amendments on September 30, 1974. In 1975, the BIA certified that the Delaware Tribe's amended bylaws provided “the legal entity which in the judgment of the Secretary of Interior adequately protects the interest of the Delaware Tribe of Indians pursuant to the [1972 Appropriations Act].” Due to suit filed by the Kansas Delaware, a non-recognized tribe, BIA reviewed all federally recognized Delaware tribes' legal documents. Then in 1979, BIA revoked the Delaware Tribe of Indians' status, citing that the removal to Oklahoma in 1879 with the Cherokees effectively placed the tribe under the authority of the Cherokee Nation. The BIA had determined that the Department of the Interior would generally engage in government-to-government relations with the Delaware Tribe only through Cherokee Nation, and that the Department would engage in direct relations with the Delaware Tribe solely with respect to the Tribe's claims against the United States.
The Delaware Tribe of Indians regained their federal recognition by the Secretary of the Interior in 1991, when the BIA rescinded their 1979 decision. However, the Cherokee Nation disagreed with the decision and filed suit against the BIA and the Secretary of their decision. The Cherokee Nation's position was upheld in court, leading to the Delaware Tribe's loss of federal recognition. After years of negotiations, the two tribes resolved their differences through an agreement in October 2008. Delaware voters approved the agreement and voted to reorganize in May 2009, under the authority of the Oklahoma Indian Welfare Act.
On July 28, 2009, The United States Department of the Interior notified the tribal office in Bartlesville, Oklahoma, that the Delaware are again a federally recognized tribe. www.wikipedia.com