Richard Gamble discusses  the “vanity of American exceptionalism” in his review of a short book by Charles Murray:
On a return visit, Tocqueville would find 21st century Americans still seeking flattery from others and flattering themselves. This appetite for praise was not a credit to the American character in the 1830s. Nor is it now. Our preoccupation with being exceptional, with figuring out just how exceptional we are, and then constantly reminding ourselves and insisting to the world on the indubitable truth of that exceptionalism is not attractive. Like all vanity, it impedes self-knowledge. And it forgets its indebtedness to the past.
It is one thing to acknowledge and value America’s constitutional system and political principles, and something else entirely to treat these things as a cause for endless self-congratulation and justification for whatever it is that the U.S. happens to be doing around the world. As Gamble notes, this has a corrupting effect at home and is obnoxious to everyone else. Unfortunately, when people refer to “American exceptionalism” now, it is often done to praise ourselves and then to dictate to other nations on the grounds that we are uniquely suited to do so.
This is familiar territory for Prof. Gamble. He wrote a TAC article  on the same subject last year, and wrote In Search of the City on a Hill: the Making and Unmaking of an American Myth  to investigate the origins and uses of the “city on a hill” rhetoric that now regularly crops up in appeals to American exceptionalism. As he wrote in his article last year, there are two competing traditions of American exceptionalism:
The old exceptionalism was consistent with the ethos of American constitutional democracy; the new is not. The old was an expression of and a means to sustain the habits of a self-governing people; the new is an expression of and a means to sustain a nationalist and imperialist people. The old exceptionalism suited a limited foreign policy; the new suits a messianic adventurism out to remake the world.
As we have seen once again in the last few weeks, Americans have no appetite for such adventurism. That doesn’t mean that they reject all forms of American exceptionalism, but rather that they have started rejecting the warped version of the concept that exploits Americans’ admiration for our country’s good qualities into a mission to meddle in the affairs of other nations all over the world. If the new exceptionalism is one that vainly seeks praise and power, the old one prizes modesty and humility in our conduct in the world.