Historian Patrick Wolfe argued that in settler colonialism, "invasion is a structure not an event." That means the taking of land is not over; it continues through laws, borders and institutions that keep it in settler hands. The aim is to eliminate Native people as nations, through killing, removal or assimilation.
US law followed this pattern. In Johnson v. M'Intosh in 1823, the Supreme Court used the Doctrine of Discovery to rule that European discovery gave the US title to Native land. The Indian Removal Act of 1830 forced nations from the Southeast onto lands west of the Mississippi. Under the Dawes Act of 1887, tribal landholdings fell from about 138 million acres to about 48 million by 1934. The Homestead Act of 1862 gave settlers, almost all white, about 270 million acres, much of it taken from Native nations.
Settler colonialism explains present-day issues like disputes over water rights, pipelines on treaty land and jurisdiction on reservations. It is also why movements like Land Back frame justice in terms of land and sovereignty, not only inclusion.