Every nation seems to have an ethnic hegemony that establishes the leadership of a country. For the United States it seems to have been the Anglo-Saxons who dominated politically and culturally. Nowadays the ethnic distinction of White Americans has largely vanished and is coded primarily by race. With this in mind:
How exclusive was the Anglo-Saxon identity in early America?
How much of American society was culturally shifted towards (or controlled by) Anglo Saxons?
When did America cease to be so specific with Anglo identity and ethnicity in general, and how were other ethnic groups integrated as a result of this?
Lastly, I would just like to link this article as a point of reference for my questions: https://www.bbc.co.uk/bitesize/guides/zkng87h/revision/1
While I can add nothing to the particular question here (I am a historian of the early medieval period), there's an important historiographical point to raise here. 'Anglo-Saxons' are not an ethnic grouping, nor have they ever been. The term 'Anglo-Saxons' represents a distinct (material) cultural, chronologically defined, identity. You cannot be an 'Anglo-Saxons' unless you lived in England between let say (for the same of simplicity) 410 and 1066. There is a particularly lively debate going on in the discipline at the moment about whether the term 'Anglo-Saxons' is acceptable within any context at all - wherever you fall on the argument, it is clear that it does not represent an ethnicity.