What kind of changes would we have to make in history to make 20% of the 2007 US population (nearly) 100% native american? Id prefer not to have really independent native american states in the north american continent (barring "mega-reservations"). Would reservations really exist for that matter? What would the effect on US politics be? The Vietnam war? Any war for that matter? What about media and music?
Somehow avoid Indian Removal starting with the Cherokee in Georgia, and allow that to establish a precedence for Native assimilation to colonial culture.