Historically speaking, it heavily depended on where you were. Supposedly many East-Cast tribes, especially the Cherokee were already conglomerates of several other tribes.
Horses were also a new element in the world of Native Americans, and surely had a good bit to do with leveling the playing field between warring tribes.
source: old man wisdom, dyor
I have a soft spot for that shitty movie. The prison scene was fucking great with the chain and the teacup, those villains with the insanely actually sick lore that was way overdeveloped for one movie, the fucking sun that burns one planet's side as it revolves?!