"American Exceptionalism" goes back quite a ways but for those who pay attention to the Foreign Policy "establishment", its a key term in their discourse.
Presidents must always claim the "American Exceptionalism" ground, and even though Obama never truly deviated from that script, his timid little steps outside the neocon lines had THAT crowd claiming he denied "American Exceptionalism" on his international "apology tour", and this was basically a sign that Obama was not really on board with being a Real American. Of course if you paid attention even to Candidate Obama, it was clear he was 100% on board with American Exceptionalism.
So it's a bit of a litmus test to be a respected member of the establishment. Those that take issue with the concept and challenge it are relegated to the fringes of discourse (see: Chomsky, Herman, Hofstadter, etc)
But I think actually the concept itself is dangerous for America, because the "American Exceptionalism" idea is essentially the foundational brick for their foreign adventurism, it is their version of the British "civilizing mission"....
Bacevich's takedown of David Brooks
posted yesterday in Salon was brilliant, but to give you a real flavour of "American Exceptionalism" in the foreign policy establishment, not many better than Brooks to embody it. The Iraq War:
"represents what the United States is on earth to achieve. Thank God we have the political leaders and the military capabilities to realize the ideals that have always been embodied in our founding documents.”
Its a quasi-religious, foundational element in their national mythology. And the problem with it is it paves the way for the neo-imperialist agenda (as long as it can be shaped into a form that satisfies the requirement that America can portray itself as heroic and "saving" civilization). Brooks and so many others
honestly believe the "American Exceptionalism" myth, even in the face of the biggest foreign policy disaster of a generation (Iraq), coming on the back of another failure (Vietnam) that together should put the lie to American's perception of their own invincibility and power to shape the world.
Even now in Syria they think they can bend things to their interest - based more on the power of this myth than anything else. To me, this is the biggest thing that drives America to war: way more than oil, way more than money, way more than PNAC, the rothschilds or the Bilderbergers put together! It is the grease on the wheels of the war machine...