A Staggering Statement about George Whitefield's Influence

I have not read much written by George Marsden. But what I have read seems to indicate, to me at least, that he tends to be understated and reserved in his assessments. Which makes the following assessment of Whitefield all the more staggering, even shocking:

George Whitefield not only changed Jonathan Edwards's life; he changed American history. His influence was so great that he ought to be considered as one of America's leading founding fathers. One reason he is not, of course, is that he was not an American, but remained based in England, even though he visited America a remarkable seven times and died in Newburyport, Massachusetts, in 1771. Another reason why he is not as well remembered as others who shaped early America is that he was a religious figure, not a political one. Nonetheless, during his lifetime he was almost certainly the best-known person in the colonies, even more widely known among ordinary Americans than was his friend Benjamin Franklin. He was the first celebrated "star" in an emerging popular culture that, lacking hereditary aristocracy, would be particularly susceptible to stars. Not only was he famous: Whitefield revolutionized American religion, and hence much of American life. 

—George Marsden, A Short Life of Jonathan Edwards (Grand Rapids: Eerdmans, 2008), 60.