How did many American Indians respond to the government policies?

Answer 1

Your question implies a racial stereotype. There are hundreds of American Indian tribes. Some of the tribes like the Iroquois had complex social orders that were quite progressive, other tribes more resembled modern street gangs. Some were agrarian, others were almost purely hunter gathers. Some were more monolithic, others were considerably more individualistic.
The American Indians that sought assimilation often did well in dealing with the Federal Government. But remember, the political policies that affected citizens were often made at state and local levels. Federal law has become progressively stronger but the U.S. was founded as a union of states.
Travel to Wyoming or Arizona or South Dakota and you will see Native Americans living in abject poverty with much too short life spans. They have not received a fair share of education or health care.
Investigate major cities and you will find many people with Indian ancestry living normal and happy lives.
It all depends who you talk with.