https://www.govinfo.gov/app/details/STATUTE-71/STATUTE-71-Pg...
is an example. Currently however congress has tried to improve / make up for prior poor treatment of native americans - but the power is ultimately in congresses hands (with some small limits).
Trump was active in this more recently
https://www.theguardian.com/us-news/2020/mar/31/trump-admini...