Judging from your other questions, I would guess the Aztecs, because they had an extremely advanced civilization relative to their time period. However, you might want a second opinion to verify this. Hope this helps.
Checks and balances? that might not be right i’m not sure
To show his support for the federal government's authority to tax.
Monroe doctrine was the thing that blocked other nations from coming into americas. It was enforced by the british military who were the strongest at time.
Many nations accepted this out of fear of their military.
