Has there been a predominant view of what an American “should” look like in our history?

200-300 word that answer the questions Has there been a predominant view of what an American “should” look like in our history? Most of us have been told that America is a melting pot? Do you find this an accurate description? If so, what does what we melt into look like? Would you have been welcomed in the U.S. in the period we just covered? What about now? ( years 1890-1920)