She carefully planned a five-hour drive to the polling place in her Tennessee hometown to vote on Election Day. She considered the traffic, the weather, the surging coronavirus pandemic and — something she never imagined having to contemplate — the possibility of civil unrest in the aftermath of an American election.

The last four years have delivered so many shocks that anything seemed possible to Lacey Stannard, the wife of a soldier. She had tried to get an absentee ballot sent to her home on a military base on the other side of the state. But the clerk in her hometown refused. A part of her thought it was crazy to drive 10 hours roundtrip to cast a Democratic vote in deep-red Tennessee, but a larger part thought it was worth it to register her displeasure.

Americans voting on Election Day are exhausted from constant crises, uneasy because of volatile political divisions and anxious about what will happen next. Like those who cast ballots early, their agony is not in deciding between President Donald Trump or his Democratic challenger, Joe Biden. Most made that choice long ago.

Instead, those voting in record numbers say basic democratic foundations feel suddenly brittle: Will their vote count? Will the loser accept the result? Will the winner find a way to repair a fractured, sick and unsettled nation? Stannard, a 28-year-old mother of two, hit the road Monday evening to arrive at the polls early on Election Day, only to turn around and rush home before an uncertain conclusion might aggravate a nation already on edge — fear she blames on the president''s penchant for pitting people against each other.

“When the election results start trickling in, I would rather be safe at home, which is sad because never in my life... would I have thought I have to hurry up and vote and get home so that I wouldn''t have to be fearful,” she said. “Which is one of the reasons I''m driving five hours to vote because I shouldn''t have to feel that way.” Across the country, Americans say the stress of this election has made them physically ill. Others have obsessively tracked polls to soothe their nerves, or bought guns, or researched moving abroad, or retreated to a cabin in the woods. Tension has ratcheted up, as each side believes the other is threatening to usher in the end of America as we know it.

On Tuesday morning in the critical battleground suburbs of Detroit, 57-year-old Karama Mishkoor and her daughter planned to vote, go to work and immediately head home.

“Please, please, please don''t go anywhere else," Mishkoor begged her daughter, 24-year-old Ashley.

Mishkoor, a devout Catholic and immigrant from Iraq, said she fled that country decades ago for peace, stability and freedom, and she''s sad that now this nation seems so shaken. They support Trump, but didn''t put signs in the yard because there''s so much anger.

Ashley Mishkoor said she''d seen the partisan vitriol piling up on social media and wondered: What if that cracks open in real life? “This week is really scary," she said.

“I''m just hoping, whatever way it goes, there''s peace in our country." A nation already uncertain about its future amid a worsening pandemic, an economic sucker punch and series of police killings that forced a national reckoning on racism is now contemplating the added threat of possible clashes in the wake of Election Day.

Caravans of Trump supporters clogged traffic around the New York metropolitan area this weekend. In Texas, cars and pickup trucks festooned with Trump flags swarmed a Biden campaign bus, sometimes boxing it in. Trump criticized the F.B.I. for investigating the incident, calling the drivers “patriots.” Weeks ago, a group of men were arrested for allegedly plotting to kidnap the Democratic governor of Michigan. Gun sales are through the roof. Last week, Walmart announced it removed ammunition and firearms from displays, citing “civil unrest.”

Trump has refused to promise a peaceful transfer of power. He told a far-right group to “stand back and stand by.” About 7 in 10 voters say they are anxious about the election, according to an AP-NORC poll last month. Only a third are excited. Biden supporters were more likely than Trump voters to be nervous — 72% to 61%.

But Trump's supporters, too, said they feel a sense of dread. The president has warned them that if he loses the country would lurch toward socialism, crime would consume the streets, freedom would buckle under political correctness.

“If we let that other guy in, all hell is going to break loose,” said Dan Smith, 53, who is retired from law enforcement in Norfolk, Virginia. He said he''s supporting Trump because he''s concerned about “law and order.”

As the coronavirus crisis surges to more than 9 million infections and 230,000 dead, the election for many is a referendum on how Trump has handled the pandemic. In the final days of the campaign, he has continued to downplay the toll it has taken, and many of his supporters say they find no fault in his response.

In New Albany, Ohio, Jason Baker, a 44-year-old real estate agent, said that despite the fact that he and his family all had COVID-19 two months ago, he cast his ballot for Trump. He believes the pandemic has “been highly politized to the point where it''s disgusting.” He described his vote as “a chess move” toward protecting the issues most important to him: law enforcement and the economy.