“It’s gotten worse since Trump came after me,” she said.

The president’s attack, and the way it was received by some of her constituents, was a lesson in the conflicting emotions and priorities of being a Trump supporter. At the Rotarian dinner on Saturday night, Ms. Dingell was embraced by an old friend, a retired utility company manager named Bill Jasman, who was disturbed by what the president had said about her husband. “Generally, I do like the things he is attacking, like China,” Mr. Jasman said, but not in the case of the late Mr. Dingell.

Still, Mr. Trump’s vitriol against his friend won’t change his mind come November, he said, when he plans to cast ballots for both the president and Ms. Dingell. “Ninety percent of it is good,” Mr. Jasman said of the president. “Ten percent of it is toxic. So you don’t throw the baby out with the bath water.”

About 10 miles further north at a Lebanese restaurant in Dearborn, where two Dingell yard signs greeted patrons out front, a group of about two dozen Muslim men debated the merits of Mr. Sanders and Mr. Biden as the potential Democratic nominee, and Mr. Trump as president. One of the men, Ali Jawad, the owner of an oil and gas distributor, said he thought Mr. Trump had been doing a good job and was considering voting for him in November. The economic progress made in Michigan since the Great Recession, he said, was hard to argue with.

Mr. Jawad believes Mr. Trump could outperform expectations in Michigan again, just as he did in 2016. He said he realized there was a groundswell of support building after driving south through the Downriver communities on his way to Toledo. “There were Trump signs everywhere,” he said. “And four years before I didn’t see one Romney sign there.”

Wages are indeed rising, and there are more jobs. But wage increases for lower earners are being eaten up by inflation. And job growth in the Dearborn area has been small. Economists say Michigan may never regain all the jobs it lost when the auto industry collapsed during the last recession.

Mustapha Hammoud, an engineer who is just a few years out of college, said he wasn’t at all surprised that there were Muslims who would vote for Mr. Trump in Dearborn despite the president’s history of making disparaging remarks about their religion and his attempt to deny certain Muslim immigrants entry at the border. For many, immigration is an out-of-sight, out-of-mind issue, he said.

“We hate the fact that we don’t have health care,” he said. “We hate the fact that we don’t have jobs. And we hate the fact that our parents are always telling us that we’re lazy,” he said.