A country is a land and a people. A people, in turn, are constituted by interlocking networks of common ways, memories, and understandings, together with symbols that serve as rallying points, all of which enable them to carry on life together and look forward to a common future.
So who are the American people? The question is not likely to have a unique natural answer, since there are degrees, overlaps, and mismatches, but conditions limit possibilities. Benjamin Franklin, born in Boston and settled in Philadelphia, thought of himself for most of his life as a British subject. As time went on conditions changed, and with them his outlook, and he became an American first and foremost. (Those who remained loyal to the mother country had to move to Canada.)
After America stopped being British in nationality she remained largely so in heritage. In the Federalist, John Jay described Americans as
one united people, a people descended from the same ancestors, speaking the same language, professing the same religion, attached to the same principles of government, very similar in manners and customs.
The purpose of the Constitution was to provide for the common welfare of that people and their posterity, and that was indeed the purpose of American government in the period that followed.
Ambiguities as to the nature of America and her...