A forgotten word in America is “assimilation” and we are the worse for it.
It worked in the late 1800’s when America was led by a competent population. Assimilation now is a joke.
I remember in gradeschool, we were taught that America was a "melting pot" where people came from all over the world and became American. This was later changed, and we should consider America a mosaic - a single picture but with each individual retaining a unique identity.
Europe is discovering it needs a melting pot.