Earlier quoted context omitted.
Diversity, as understood as a possible problem for social cohesion, is not about race: it's about culture. And the vast majority of Americans in the US have only one culture: the American one. The exception for this is first (and sometimes second) generation immigrants. That's why I use the native vs foreign born statistic.
> And the vast majority of Americans in the US have only one culture: the American one. I don't think there is one unifying American culture. There are some common cultural elements, but there are fairly distinct regional (as well as racial/ethnic) cultures in the US.
If the US would not share a culture, intra-US migration would be a big issue, as it is in the EU.