“I don’t care if I lose clients,” said Lynne Jones, an interior designer raised in burning-red Paducah, Tex., wedging a stack of Beto O’Rourke signs into her car over the summer, part of what she described as the most serious political engagement of her 62 years. “Politics is a dirty business, I’m discovering.”

The right speaks with gratitude for a White House dream realized.

“We believe he’s sent from God,” Kathy Kiely, 67, said of Mr. Trump from a mall food court in Prescott, Ariz., “to bring us back to where we used to be, and where we can be.”

More common, though, are the darker appraisals: of enemies real and imagined, of what awaits us if the national rupture remains.

“History always repeats itself,” said Robert Brock, 42, a Trump-supporting truck driver in South Daytona, Fla., forecasting a kind of modern civil war between conservative and liberal. “People aren’t realizing that.”

In flashes, the race’s final weeks have lurched from abstract menace to notes of genuine violence. Mail bombs targeted Mr. Trump’s Democratic opponents. The president praised and re-enacted a congressman’s assault on a reporter, to cheers and laughter inside a Montana airplane hangar. He suggested that the military should fire upon migrant rock-throwers at the southern border.

And inside the Volusia County Republican office, where Mr. Brock spoke of looming combat after a rally for the statewide ticket, gunshots had shattered a front window last week, piercing a poster with the president’s surname. By the weekend, the sign was up again, with a hole visible just above the “R” — a message to whoever had done this, to whoever doubts the tenacity of the president’s people.