Anthropology

on the colonies to unify, and later had some influence on the delegates at the Constitutional Convention, but I don't think that I would say that it was the basis of the constitution. The US founders were also familiar with the systems of ancient Rome and Greece. A colonial governor of NY, Cadwallader, compared the Iroquois system to Rome's republic.

For the Iroquois (Haudenosaunee) founding story of their government, and a description of how the system of government worked, I recommend the book Parker on the Iroquois. Arthur Caswell Parker was biologically 1/4 Seneca, but not a member of the Seneca nation until he was adopted into a clan, because his mother and grandmother were of English descent.

Parker lived from 1881 to 1955. He was a NY archaeologist and ethnologist. (He was also a distant cousin of mine.)

https://www.amazon.com/Parker-Iroquois-State-Studies-Syracuse/dp/0815601158

https://en.m.wikipedia.org/wiki/Arthur_C._Parker