Not really that liberal, compared to what the people they colonized were doing, before the europeans arrived.
You are correct, actually. Not sure why you are downvoted. Several traditional tribal government structures of indigenous peoples were much more democratic in form.
However, besides the Iroquois Confederacy, it’s hard to consider them as being sufficiently organised to be considered a state in the traditional sense. This isn’t meant to exclude all indigenous governments; the Aztec, Mayan, and Inca civilisations were all examples of (non-democratic) highly organised states, especially in comparison to the North American tribes around and after European contact.
I don’t think that being/having a state is necessary for a democratich governance. I don’t know why you added that conditional.