What was the policy of the American government toward the Native Americans in the late 1800s? How did that policy affect the Natives?

Toward the beginning of the 20th century there were roughly 250,000 Native Americans in the USA – simply 0.3 percent of the populace – generally living on reservations where they practiced a restricted level of self-government. Throughout the nineteenth century they had been denied of quite a bit of their property by constrained evacuation westwards, by a progression of deals (which were frequently not respected by the white specialists) and by military loss by the USA as it extended its authority over the American West.  

In 1831 the Chief Justice of the Supreme Court, John Marshall, had endeavored to characterize their status. He pronounced that Indian clans were 'homegrown ward countries' whose 'connection to the United States takes after that of a ward to his watchman'. Marshall was, as a result, perceiving that America's Indians are special in that, in contrast to some other minority, they are both separate countries and part of the United States.

Explanation:

the first forms of writing came from them in the form of pictographs around 3100 bc.