And, as I posted above, George Washington spent a good portion of his final public communication warning against the sort of regional and party factionalism that would lead to the dissolution of the Republic.
I think the key phrase is right here:
"Citizens, by birth or choice, of a common country, that country has a right to concentrate your affections. The name of American, which belongs to you in your national capacity, must always exalt the just pride of patriotism more than any appellation derived from local discriminations."
Washington considered himself a citizen of the United States. His loyalty was to country over state. As it should be.