But even as they square off, they are careful with each other, reaching out to pat an arm or clutch a hand, sometimes even backing down a bit. Ms. Walls told her friend that she agreed it was unseemly for a president to act that way. “He should have been quiet, showed a little bit more integrity,” she said. “But I did laugh, and I agreed, and it sounded from that crowd like everyone agreed.”

DeSoto County, where Southaven is located, voted overwhelmingly for Mr. Trump, 66 percent to 31 percent for Hillary Clinton. It was a small hamlet until the 1970s, when the suburban population expanded as courts ordered busing in nearby Memphis. An explosion of Memphis-based freight services like FedEx and Southaven’s highly-regarded public schools drew more families, black and white. Now Southaven is the third-largest city in Mississippi. It’s a place of pleasant, if often treeless, subdivisions and large strip malls, with no central downtown. Dale’s, which opened in 1966, stands out for its bright pink exterior and is one place friends can find each other, along with church and school.

Southaven is 71 percent white and 22 percent black, according to the 2010 census. Because most of its housing was developed after the 1970s, neighborhoods are generally integrated, and so are schools. But political loyalties appear starkly divided by race — nearly every white person interviewed in the area backed Mr. Trump, and every black person opposed him.

Candy Jordan, a black office administrator, blames the president for incidents of racial hostility that she had never experienced before his election. She said her daughters’ friend was called a racial epithet by an elderly neighbor who accused the teenager of ruining her flower bed. “There’s a difference between following a person and following what’s right,” she said.

By contrast, Jill Gregory, who is raising three children in the nearby town of Olive Branch and is white, said, “Trump is the only president that’s been elected and he doesn’t have any other interest than serving the American people.”

And so it went at Dale’s, despite the evident affection of the staff for each other. Ms. Green said all the Trump supporters she knew were white, prompting an uneasy rejoinder from Melissa Thomas, the general manager. “What does that mean?” said Ms. Thomas, herself a fervent Trump backer. Last week, she and her daughter, Ms. Gregory, had made sure to be at the rally site by 6:30 a.m., nine hours before it was scheduled to start.