Tocqueville notes that Americans are very touchy in their nationalism.
Yet America is about the easiest nation to join - e pluribus unum means that we take the masses, huddled and otherwise, from anywhere and everywhere. If you embrace American principles, and profess loyalty to the nation and its Constitution, you can be an American.
I think these facts are two sides of the same coin. American expressions of nationalism are so touchy, and often so excessive, because our nationhood is so obviously constructed.
And I would expect that the people touchiest about our sacred nation would be those people who are Americans by experience, rather than formal knowledge. Their vehemence against those they claim "violate the Constitution" is in inverse proportion to their actual knowledge of the Constitution.
Today's point is a subset of my larger argument that most people's religion really is the civil religion of the nation; they believe that all of the things they hold sacred fit neatly under the national umbrella, without being able to explain exactly how.