No single historian has been so closely associated with the affirmative response to the exceptionalism question as Frederick Jackson Turner. According to Turner, who presented his famous Frontier Thesis in 1893, what made the United States unique was the frontier experience, that movement of European-Americans from the East into the "open" spaces of the West. The crucible of the frontier forged the American character as independent, rugged, and democratic. The frontier experience, Turner maintained, explains America's departure from its European roots.That's it, really.
Friedman's piece is fine. I could use it in my classes. But he obviously thinks its funny that conservatives have turned exceptionalism into a partisan wedge, so he highlights how Stalin "first used" the term. In fact, American exceptionalism has a long pedigree in American history and the "frontier thesis" is an especially important iteration of the idea --- and deserves more prominent mention in such a review than does the Soviet dictator's usage.
RELATED: From Herman Cain, at the American Spectator, "In Defense of American Exceptionalism."