Donald J. Trump won the presidency by riding an enormous wave of support among the working-class white voters.
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 American elections gave even more reason to think Mrs. Clinton was safe. National exit polls suggested that President 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 Mr. Obama’s winning coalition broke hard to the Republicans.
The Wyoming River Valley of Pennsylvania — which includes Scranton and Wilkes-Barre — voted for Mr. Trump. It had voted for Mr. Obama by double digits.
In the key battleground of Florida, Mr. Trump built his support largely on voters who expressed deep dismay with Washington. Nearly nine in 10 of his voters in Florida said they were dissatisfied or angry with the state of the federal government. Just as many disapproved of Mr. Obama’s job performance, and three-quarters thought the president’s health care law went too far.
Nearly four in 10 Florida voters said they were most interested in electing a president who would bring serious change, and Mr. Trump won that group by a broad margin. Mrs. Clinton won voters looking for a compassionate, experienced or more judicious leader — but it was not enough to cancel out Mr. Trump’s support among those hungry for change.
While Mrs. Clinton did better than Mr. Trump among nonwhite voters in Florida, it was not enough to offset his success with white voters, who skew older in the state. He won those by nearly 2 to 1, including those with a college degree. One-quarter of Florida’s electorate was white and over 60. Mr. Trump pulled most of his support from the Gulf Coast and the central part of the state, a hub for wealthy retirees, offsetting Mrs. Clinton’s gaping lead in the Miami and Orlando areas.
Mr. Trump also did well in Ohio, where voters ages 18 to 29 were 11 points less likely to support the Democratic candidate and in North Carolina, 30 percent of voters were nonwhite, and Mrs. Clinton won this group by a 62-point margin (79 percent to 17 percent). Mr. Trump, countering with a strong showing among whites, won the state.