The general way it worked as America expanded west was this.
1. Encourage settlers west into "empty" land for opportunity using various government benefits, typically free land.
2. Natives who already live there defend their property.
3. Government declares natives violent savages for defending themselves.
4. Government attacks the evil violent savages to defend the poor innocent people who were attacked for no reason (that was reported in the newspaper)
5. The people support the attacks because they are only seeing the approved pieces missing narrative.
6. The natives defend themselves from the military invaders.
7. Goverment declares the natives have now started a war by attacking "peace keeping" troops.
8. Win war.
9. Oh look actually empty land we should sell this to our citizens or make a park or something after we swipe a few artifacts for our museums.
10. Profit.
Not REALLY America specific. This was the general playbook for colonizing around the globe.