One of the problems with the idea of “American exceptionalism” is that it exacerbates a kind of complacency common to man. This is the phenomenon whereby people often view themselves as exceptions, saying, after some tragedy, for instance, something such as “I never thought it could happen to me.”
On a national level — and this especially plagues great nations — this manifests itself in the notion that “it” could never happen here. Oh, the “it” could be descent into tyranny, domination by a foreign power or dissolution. Or, maybe, it could be the election of a leader who is a Manchurian candidate, a traitor within, someone bent on destroying the nation that gave him everything. That…“it”…couldn’t happen here. In fact, the idea is so preposterous to many Americans that, if such a threat loomed, they would never see it coming. And they would call a person who warned of it a nut.