To what extent did the idea of assimilation succeed and fail in regards to Native Americans?

Answer: The assimilation of the Indians failed the moment it began.

Explanation:

The complete collapse was experienced at the outset because the assimilation of the Indians was violent. The suppression of their culture, the seizure of land, and discrimination have had profound consequences on the indigenous population of America. All of this has been around for a long time throughout history, which has had a profound effect on the indigenous people. Millions of Indians did not survive decades of European domination. War conflicts, the spread of infectious diseases, the forcible transfer are just some of the factors that have decimated the natives.

Because of all the above, it is impossible to speak of the successful assimilation of the Indians. A number have indeed left remarkable footprints throughout history, such as the Joseph Medicine Crow. Even today, there are people in American society who are influential and hold some positions, such as Elizabeth Warren. But that's just a small number of people. Even today, Indians are a largely marginalized and discredited factor in American society.