Welcome home mate.
Some claim it was foundational or even that the US system was based on the Iroquois Confederacy, but both positions are difficult to reconcile with the history of the development of US political thought in the years leading up to the American Revolution, and the extremely heavy influence of (European) Enlightenment writers and Old World political systems on the US. Furthermore, there aren’t many structural similarities between the two systems.
Its influence, such as it was, should be seen as more in the form of cultural diffusion, assisting the normalization of consensus-government as an alternative to majority-government, and reinforcing pre-existing beliefs about decentralized polities being viable.
What do you mean?
They were aligned with Brits against the French, and fractured over supporting America or England during the revolution.
They kind of cancelled themselves out of it. They should have taken the opportunity to secure their own lands against all the European’s. They stood a chance, and would have been a refuge for other tribes making them a power house in the North East long before America got its shit together.

