It was Benghazi that put her over the edge, she said.

For Mr. Crano, a former steelworker who retired after a second career at the Pittsburgh airport, it was abortion and same-sex marriage. “If you’re a Christian, you can only vote for Trump,” he said the day before the election at K & N restaurant. It is one of the few thriving businesses still left on Merchant Street, which old-timers — and there are now mostly old-timers — remember as once so crowded you bumped into people. Now it is largely deserted.

The Cranos were having breakfast beneath a poster of Elvis with several friends, all fierce Trump backers. They painted a desperate vision of America if Mrs. Clinton won, predicting a wave of terrorism by unvetted refugees and a slide into dictatorship.

“I’m going to the bank and taking a bunch of money out and buying a lot of guns and ammo,” said Mr. Crano, a former union leader with a large white beard. “I’m going to protect mine and my family,” he added.

Ambridge, like much of Pennsylvania outside Pittsburgh and Philadelphia, eagerly enlisted in Trump Nation this year. Its largely white, less educated population (15 percent have a college degree) packed a boisterous rally that Mr. Trump held at the local high school.