Donald Trump won the presidency by riding an enormous wave of support among white working-class voters. It was always a possibility, but it had always looked unlikely. Hillary Clinton led in nearly every national poll — and in other surveys in the states worth the requisite 270 electoral votes.
The traditional view of recent US elections gave even more reason to think Ms Clinton was safe. National exit polls suggested that President Barack Obama won the 2012 presidential election despite faring worse among white voters than any Democrat since Walter Mondale. Those polls showed that white voters without a degree were now just one-third of the electorate. It was interpreted to mean that there was not much room for additional Democratic losses, especially once a white Democrat replaced Mr Obama on the ballot. The truth was that Democrats were far more dependent on white working-class voters than many believed.
In the end, the bastions of industrial-era Democratic strength among white working-class voters fell to Mr Trump. So did many of the areas where Mr Obama fared best in 2008 and 2012. In the end, the linchpin of Obama’s winning coalition broke hard to the Republicans.
The Wyoming River Valley of Pennsylvania — which includes Scranton and Wilkes-Barre — voted for Trump. It had voted for Mr Obama by double digits. Youngstown, Ohio, where Mr Obama won by more than 20 points in 2012, was basically a draw. Mr Trump swept the string of traditionally Democratic and old industrial towns along Lake Erie. Counties that supported Mr Obama in 2012 voted for Mr Trump by 20 points.
The rural countryside of the North swung overwhelmingly to Mr Trump. Most obvious was Iowa, where Mr Obama won easily in 2012 but Mr Trump prevailed easily. These gains extended east, across Wisconsin and Michigan to New England. Mr Trump won Maine’s 2nd Congressional District by 12 points; Mr Obama had won it by 8 points.
These gains went far beyond what many believed was possible. But Mr Obama was strong among white working-class Northerners, and that meant there was a lot of room for a Democrat to fall.
That fact was obscured by national exit polls that showed Mr Obama faring worse among white voters than any Democratic nominee since 1984. But Mr Obama fared very poorly only among white voters in the South. He ran well ahead of Ms Clinton just about everywhere else.
The exit polls also systematically underestimated the importance of these white working-class voters to Democrats. In general, they overestimated the number of well-educated and non-white voters.
The result was that many post-election analysts underestimated the number of white working-class voters over age 45 by around 10 million.
