I have not read the book, but for most Native American tribes in the Eastern Woodlands and Great Plains the strongest medicine was warfare. Being a warrior was not some honorary thing. A brave had to kill, steal, and count coup (Touch the enemy.) to gain social status. Among the Plains Indians stealing horses was a way to gain wealth, and all tribes kidnapped women and children to incorporate into their tribe. The Plains war bonnet of eagle feathers is like the medals on a soldier, and shows the mighty martial feats of the warrior wearing it. Enemy scalps and weapons were also displayed with pride. Pre-literate societies don't have written deeds or surveys to determine property, so ultimately might is going to make right unless there is some magic involved.

Of course the white man just wanted to make money, and continuous raiding and guerilla warfare could not go along with that, so the Indians were forced to put down the tomahawk. That was a major blow to their social structure and conception of the world.