The stress, and the added workload posed by the growing nationwide trend toward voting by mail, are taking a toll. In Kentucky, more than one in five of the state’s 120 county clerks are not seeking re-election in November, and six have quit outright this year, the state’s top election official, Secretary of State Michael Adams, said.

Ms. Ertmer, the Winnebago County clerk, said turnover also has been unusually high in Wisconsin, both among county clerks and municipal clerks who perform most election duties. “I’m going to retire next year,” she said. “I would have continued if the atmosphere was different. I love my job, and the people I work with. But enough is enough.”

And in Washoe County, Nev., home to Reno, county officials made it official policy to give legal and public relations help to government officials who are harassed or smeared after the registrar of voters, Deanna Spikula, announced her resignation in June.

All that said, Mr. Adams, Ms. Ertmer and other officials said they planned to be ready when voting begins. Mr. Adams even expressed guarded optimism that the wave of activity by election deniers had crested: “The My Pillow guy did his thing on me a week ago, and I thought I’d get thousands of records requests,” he said, referring to Mr. Lindell. “But I got very little.”

Some officials, like Anthony W. Perlatti, the director of the Cuyahoga County Board of Elections in Ohio, said they had learned lessons in 2020 that will help in 2022.

And Nichole Baldwin, the clerk and registrar of voters in tiny White Pine County, Nev., said she was unfazed by the records requests. “They’re all asking for the same thing: cast vote records,” she said. “I have them on a flash drive, and I’m sending them out as they come in. No big deal.”

Indeed, the greatest worry for many was the prospect of the unexpected.

Kaitlyn Bernarde, the city clerk in Wausau, Wis., said she was reviewing her emergency management plan, with guidelines for handling aggressive voters and rules governing the conduct of observers inside polling places.