25 USC 1300m6 - Tribal constitution

(a) Election; time and procedure 
Upon the completion of the tribal membership roll under section 1300m–4 (a) of this title and upon the written request of the Interim Council, the Secretary shall conduct, by secret ballot, an election for the purpose of adopting a constitution and bylaws for the Tribe. The election shall be held according to section 476 of this title, except that absentee balloting shall be permitted regardless of voter residence.
(b) Election of tribal officials; procedures 
Not later than 120 days after the Tribe adopts a constitution and bylaws under subsection (a) of this section, the Secretary shall conduct an election by secret ballot for the purpose of electing tribal officials as provided in such tribal constitution. Such election shall be conducted according to the procedures specified in subsection (a) of this section except to the extent that such procedures conflict with the tribal constitution.