How has the United States Federal Government impacted the sovereignty of tribes in the Pacific Northwest? It's for my CWI class. Please Y'all I need help

The U.S. government made reservations the centerpiece of Indian policy around 1850, and thereafter reserves became a major bone of contention between natives and non-natives in the Pacific Northwest. However, they did not define the lives of all Indians. Many natives lived off of reservations, for example. One estimate for 1900 is that more than half of all Puget Sound Indians lived away from reservations. Many of these natives were part of families that included non-Indians and children of mixed parentage, and most worked as laborers in the non-Indian economy. They were joined by Indians who migrated seasonally away from reservations, and also from as far away as British Columbia. As Alexandra Harmon's article "Lines in Sand" makes clear, the boundaries between "Indian" and "non-Indian," and between different native groups, were fluid and difficult to fix. Reservations could not bound all Northwest Indians any more than others kinds of borders and lines could.

answer; u.s senate;