The United States of America was created by British settlers who displaced the American Indians and created a new nation built on English language, law, and culture, and out of ideas that had been floating around during the English Civil War. In the 20th century we came up with these feel-good narratives about immigrants to help assimilate the massive number of immigrants that we had taken in during the late 19th and early 20th century. But we did that at the same time as we severely restricted immigration under the 1924 Johnson-Reed Act.

And even though British Americans long ago became a minority--the single largest ethnic group is Germans--there is shockingly little influence from any other group in America's core political, legal, and civic institutions. Our constitution and laws have more ideas from ancient Rome and Greece than from all contemporary foreign cultures combined. The Ivy League schools that still dominate our bureaucratic and professional class were founded by British Americans as copies of Oxford/Cambridge. Silicon Valley arose around Stanford University (Stanford being an English surname) and a U.S. military that at the time was still dominated by British Americans. Wall Street is a direct descendant of London's financial sector, though it has some influence from New York's history as a Dutch city.

That's the reason the United States is economically, politically, and culturally more similar to Australia than to Mexico, despite being on the opposite side of the planet from Australia and diverging politically 250 years ago. To the extent the U.S. is an "immigrant nation," that is only in the sense that many immigrants and their descendants happen to live here. But those immigrants are governed and organized by the (now nearly dead) hand of the Anglo-Protestants, through their law, norms, principles, and institutions.

A good bit from the late Justice Scalia on this: https://www.facebook.com/TrueTexasProject/videos/antonin-sca...