Every nation began as immigrants. Stupid argument.
But the origins of the concept of America, as an ethnic people, derived not in the immigrants who came later, but in the development of new communities by settlers who defined & perpetuated their own culture, eventually breaking away from their old world roots, when the existing Government had infringed on the implied social contract with those settlers.
America was born in what was a Counter-Revolution against outside control, which had become more meddlesome & foreign after the French & Indian War.
Failing to recognize the essentially American character that emerged from the interactive experience of those settlers, in an effort to make those descended from later arrivals--such as myself--feel good, is really to play into the hands of those internationalists, who would like to make believe that everyone is interchangeable, in order to suppress all the things which make any nation unique.
It also plays into the hands of those who want to continue to flood our lands with immigrants who do not share the cultural values, which once distinguished both the original American settlers, and later arrivers, who were drawn here by the appeal of those values.