The Dakota people were chased out onto the Western prairie and into Canada. It took almost another 30 years till the Battle of Wounded Knee in 1890 to complete the many battles and actions.
Actually, from about 1650 till 1890 Europeans fought Native Americans for this continent. You can debate, if you wish, the rightness or wrongness of these conflicts, but the fact remains it took this long to subdue a primitive, dangerous enemy who possessed great courage and determination.
We, then, have a historical precedent for a long and bloody war. Like it or not we will have to prevail.
When two cultures are incompatible with one another and they are in conflict, then "right" and "wrong" are essentially irrelevant. Only "winning" and "losing" matter.