The Seneca Nation of Indians came into formal existence in 1848 when they abolished the "chief" system and established a constitution with elected officials. The constitution provides for an Executive Branch, a Legislative Branch, and a Judicial Branch. The Executive Branch is comprised of the President, Treasurer and Clerk, who are elected every two years and may not succeed themselves. The Legislative Branch (or Tribal Council) is comprised of 16 members; eight from the Cattaraugus Reservation and eight from the Allegany Reservation, who are elected for 4-year staggered terms. The Judiciary Branch is comprised of separate Peacemaker, Appellate, and Surrogate Courts.

The Seneca Nation government is a true democracy. In fact, most of the United States government is based on the democratic style of the Iroquois Nations. The current government officers are:

Under the leadership of elected officials, the Seneca Nation of Indians has generated revenue through a variety of means, including a number of leases entered into by the tribe and various enterprises. The SNI operates several tribally motivated programs and projects in the areas of education, health, recreation, and culture that have come into existence for the benefit of present and future generations of Senecas. The SNI is also a major employer of Seneca members and maintains an effective Multi-Server WAN Network for accounting, payroll, data retrieval, and record keeping.

Class III Gaming Compact (PDF) | Treaty of Canandaigua