Only the blue and possibly the yellow wedges of that pie derive from places that the contemporary U.S. majority thinks of as the source of the North American culture.
That's changing, but this takes time. As has been true since Europeans invaded this continent, the future and dynamism of this country depends on immigration.
Bloomberg View, an organ of business news, is willing to let Ezra Klein explain this:
Klein concedes that new immigrant workers may, sometimes, compete with native workers who are already struggling. I'm not one to deny that; I see it in construction, in yard work, in the hotel industry -- regardless of the broad statistical picture. There are citizens who have a harder time because someone else has come along to do the dirty work. No question about that.
But it's not usually these citizens who are leading the charge against the newcomers. It is too often those of us who simply find immigrants too strange and take that as threatening. Those new people are a challenge. They won't look like us; even once they learn English (and they do, fast!) they won't speak like us; they bring different foods and different sports. But this new United States that is coming into being including all these cultural strands is our best future. Hiding our heads accomplishes nothing. We're in for yet another nasty season of backlash and haggling as immigration reform bumps along in Congress. Real, already present, neighbors are hurt by our reluctance to move ahead on this.
But -- despite the dreams of some of the white Republican base -- there's no going back. Those "foreign born" are part of our future.