What was the effect of this “frontierless” society on minorities and immigrants?

Discussion Question: In Not Like Us, Roger Daniels writes, “The notion of a closed frontier, however ambiguous that may seem to us today, was a powerful influence on contemporary minds, persuading many that growth and opportunity would be more limited in a frontierless society.” (45) Part 1: What was the effect of this “frontierless” society on minorities and immigrants? How does the end of the western frontier relate to the treatment of minorities and immigrants in the Gilded Age? Part 2: Think about recent events in the United States. What limits growth and opportunity for immigrants and minorities today?