The conversations Mr. Naughton describes may be epidemiologically out of step, but he and thousands of others seem trapped in an America-right-now vortex, a swirl of politics, belief, resentment and fear. At fast food restaurants, grocery stores, warehouses, nursing homes and anywhere else frontline workers show up each day, a deep schism has taken hold. Workers nervous about the virus find themselves at the mercy of those who aren’t.

“If I ask people to wear a mask or socially distance at work, they get mad and tell the manager. Then I have to get coached. If you get coached too many times, you lose your job,” Mr. Naughton said, referring to the company’s system for managing worker infractions. (Charles Crowson, a Walmart spokesman, did not dispute that an accumulation of coachings could lead to termination.)

Draped over this dynamic are often the stark realities of poverty, and the stresses of navigating a low-paying job in a high-pressure situation. And so an already strained situation strains further. Bitterness over masking requests, job insecurity, a run on bottled water, vaccine politics — tensions routinely boil over in his store and beyond, Mr. Naughton said.

“It wasn’t always like this. It used to be more friendly here. It’s become hostile. People are really on edge. They fight with you in the store, or with each other,” he said. “The other day a woman wanted to fight over the price of potatoes. You can even see it in how people drive, like they have a death wish.”