25 USC 1041c - Establishment of a tribal roll

(a) Approval of base roll 
Not later than 180 days after December 27, 2000, the Tribe shall submit to the Secretary for approval its base membership roll, which shall include only individuals who are not members of any other federally recognized Indian tribe or who have relinquished membership in such tribe and are eligible for membership under subsection (b) of this section.
(b) Base roll eligibility 
An individual is eligible for enrollment on the base membership roll of the Tribe if that individual
(1) is on, or eligible to be on, the membership roll of Cherokee Shawnees maintained by the Tribe prior to December 27, 2000, which is separate from the membership roll of the Cherokee Nation; or
(2) is a lineal descendant of any person
(A) who was issued a restricted fee patent to land pursuant to Article 2 of the Treaty of May 10, 1854, between the United States and the Tribe (10 Stat. 1053); or
(B) whose name was included on the 1871 Register of names of those members of the Tribe who moved to, and located in, the Cherokee Nation in Indian Territory pursuant to the Agreement entered into by and between the Tribe and the Cherokee Nation on June 7, 1869.
(c) Future membership 
Future membership in the Tribe shall be as determined under the eligibility requirements set out in subsection (b)(2) of this section or under such future membership ordinance as the Tribe may adopt.