We certainly aren't anymore.
We once were exceptional—that time has passed-entitlements, feel good education, PC, and Afirmative Action has diminished this down and been replaced by childish arrogance. We may well achive our excellence again in the future—but it has been lost for some time—I think the decline came with the fall of Saigon, and the resignation of Nixon, but it might have been with the retreat from Berut with Reagan. Each year it has become worse with the USA becoming less and less free.