In this article in The Nation, George Grandin of New York University comments

 ‘Obama’s recomposition of American exceptionalism was tactically successful, at least as measured by his 2012 reelection, which expanded the multiracial and cross-class coalition that had given him the White House four years earlier. 

‘But it isn’t sustainable, and it hasn’t even survived his presidency. There are many ways that Trump’s wildfire victory represents the death knell of American exceptionalism. America was unique, we told ourselves, because it was able to keep fringe candidates at the margin—but now Trump and his followers wield the combined power of the federal government. America was unique because its political self-governance was founded on the idea of individual self-governance, on the ability of our leaders to use reason and virtue to contain their impulses and vices (Obama was preternaturally self-controlled and self-regulated). But Trump is pure id and appetite.’

See link below to full article.