Publius has diagnosed the problem with the American right as a confusion between what is contingently theirs and what is universally true. I've said something similar, although I doubt that all American nationalism/conservatism is so implicated. Some American conservatives simply express loyalty to their own because it is their own, while recognizing that everything, America included, passes. Equally, many American cosmopolitan liberals imagine the folkways of their own globalized caste are universal when they are merely delocalized.
All this reminded me of Paul Tillich's account of idolatry and the demonic -- putting what is of preliminary or finite concern in the place of what is of ultimate concern. Some corners of evangelical Protestant theology do this deliberately, through the device of reconceiving the covenant with Israel as a covenant with the United States. More, however, do it surreptiously. God becomes identified with bourgeois morality, and with the struggle of America against its enemies, internal and external.