The Matt Damon character is a bit like the George Peppard character in "How The West Was Won". A young officer who eventually gets disgusted by breaking of agreements and resigns.The historical George Crook is worth a quick read as well. Fought in the US Civil War and then a long run commanding troops in the Indian Wars, including the Little Bighorn campaign. Probably a bit burnt out by the time of the pursuit of Geronimo.A borderline western since it is set in 1909, but "Tell Them Willie Boy is Here" (1969) does delve into some of the Native American customs and how they clash with western mores. Robert Blake, Robert Redford, Katherine Ross, and Susan Clark are the main actors - so unfortunately not much use of Native American actors.