Wll thre’s a difference.....the difference between Europe and America is Europe may have as many countries as it has ethnic groups.... In America there may be many ethnic groups but there is only one America.
For now.
Not so much anymore. We are one political entity. But there's no sense of being "one people."
There used to be, mostly. There were always divisions. New England Yankees, Pennsylvania German/Dutch, Scot-Irish Southerners. And black slaves. But it was an essentially white Protestant country.
Then came an influx of German and Irish Catholics, and Scandinavians. Tensions and ethnic rivalries ensued. But they were glossed over. America settled into being a white Christian country.
Then parts of former Mexico were annexed. Black slaves were freed. Chinese workers on the railroad. And came Italians and Jews. More diverse mixtures than previous decades, but still majority WASP.
After World War Two, lots more refugees from Europe. We were now told we were a Melting Pot, a Proposition Nation, and Judaeo-Christian rather than Christian. But still mostly White, the European ethnicities melting together.
Then the 1965 immigration reform act, and gradually increasing influx of Asians, Muslims, Afro-Caribbeans, Latin Americans. Multiple amnesties. Diversity increasing faster than we could assimilate, so that we are no longer one nation, no longer melting together, but diverse and competing interests groups, fighting over taxes and entitlements, and legal privileges.
We are no longer One America. We have many dual citizens, in fact or in their heart, more loyal to their co-ethnics and foreign countries than to their fellow Americans of a different ethnicity.