Misty Kendall stopped by the Democratic party’s tent at the Monroe county fair in southern Michigan to let them know she wouldn’t be back.

The construction company owner voted for Barack Obama twice. “He wasn’t perfect but I liked his healthcare policy at the time. That was very important to me and I thought it would be good,” she said.

But Kendall was deeply disappointed by Obama’s healthcare reforms, blaming them for a surge in her insurance premiums. Even so, she voted for him again when he ran for reelection. “I liked his foreign policies. The way that he was dealing with Al-Qaeda. I thought he was doing a really good job of dealing with terrorism, keeping the country safe,” she said.

Then came 2016.

Kendall said her vote for Donald Trump was more a rejection of Hillary Clinton, who she regards as dishonest. Now she is a fan of the president and deeply defensive of her vote for him. “People say Trump is horrible. He probably is a horrible person.

“But right now I am about the economy. It’s helping me and my family. I’ll be voting for Trump again,” she told incredulous Democratic activists at the county fair.

Her company employs 12 people renovating buildings in Detroit, about 25 miles north of Monroe county, which is a 90% white and mostly working-class county of about 150,000 people. Its main city, also called Monroe, has a population of around 20,000 and much of the county’s industry.

Kendall’s vote contributed to one of the largest swings across the US from Obama to Trump. America’s first black president won Monroe county, twice, albeit by a slim margin in 2012. Four years later, Trump trounced Clinton in the county, winning 58% of the vote, the largest proportion there since Ronald Reagan in 1984.

That delivered Trump’s slim victory in Michigan, which was crucial to putting him in the White House. Trump won the state by just 10,704 votes, the narrowest margin of victory in the history of presidential elections in Michigan.

The flipping of counties from Obama to Trump in the Midwest – and the apparent paradox of Americans shifting from Obama to a man denounced as a misogynist, racist and bully – was instrumental in the president’s victory.

On the other side of Lake Michigan, the shift was decisive in squeezing out a victory for Trump in Wisconsin by less than 23,000 votes or 0.77% of the ballot – overturning a 213,000 vote victory for Obama in the state four years earlier.

Winning a clutch of swing counties turned Iowa and Ohio too.

This week, and at various stages in the run up to the 2020 presidential election, the Guardian is reporting from three midwest counties that swung from Obama to Trump in crucial states.

On the face of it, Trump’s slim margins of victory in 2016 key states are good reason for the Democrats to believe they can snatch them back from a president perpetually mired in controversy from his incessant tweeting and lashing out at even the mildest criticism to the launch of impeachment hearings.

And yet the Democrats would be wise not to count on Monroe county – which almost always votes for the ultimate presidential winner – to deliver victory for them, and local party activists know it.

The Trump tide

“The Trump tide came in and still hasn’t receded yet,” said Bill LaVoy, who lost his seat as a Democratic state representative for the county in the Trump surge of 2016. “We don’t know if these are permanent Republican voters now or it’s just temporary,” said LaVoy, also speaking at the Monroe county fair, which dates back to the 19th century.

Democrats in Monroe county face the same dilemma as their party nationally. Do they try and win back voters who swung from Obama to Trump by opting for a “safe” candidate in Joe Biden? Or do they look for another path to victory by mobilising those who stayed away in 2016, by giving them something to vote for with a candidate pushing more radical policies?

“Some think that the party needs to move more to the left. I’m not so sure that works around here,” said LeVoy. “I’m a moderate and I’m actually the last Democrat to win around here for the state house. I lean more towards Joe Biden.”

A party activist, Christopher Slat, interrupted.

“We’ve been trying to not run to the left and that hasn’t worked, so why don’t we try something different?” said Slat, a 30-year-old who makes videos for the local school district.

Slat suspects Trump voters aren’t coming back no matter who the Democratic candidate is. “We ran Anybody But Trump last time and she didn’t win. We might run Biden and he’s the same thing,” said Slat.

Nothing stays still with Trump for long, and impeachment has now swung into view. It’s a seismic political drama in Washington and dominates the analysis and argument of cable news. But it has yet to have the same impact in America’s heartland. Perhaps it will in time if the revelations are shocking enough or Trump’s political allies begin to turn on him. For now, Trump’s core voters mostly seem to chalking the investigation up to another Russia-style “witch-hunt”.

Slat, who backs Sanders over Biden, said the real impact may not be on Trump at all. “I don’t think it’s going to change people’s minds that much, especially if they’re already loyal to Trump. People are going to be more concerned with ‘what are the candidates going to do for me?’ instead of worrying about this drama stuff. I think there’s a sentiment even among some progressives that all presidents do this kind of stuff. This is a hit job, just another Russia investigation,” he said at the weekend.

“I do think it’s bad news for Joe Biden. I think it’s going to be a really hard sell if the impeachment is going on through the election cycle for Joe Biden to make the case if his son was taking $50,000 a month from a Ukrainian gas company while he was vice-president, and he’s saying there’s nothing illegal about that. Even if that’s true, it’s going to put him in the same bucket as Hillary where people say they’re all crooks so I’m going to stay home.”

Job market shifts

Monroe county, like Detroit, was once strong union territory. In 2008, the Ford car plant closed with the loss of 3,200 jobs just as the recession hit.

“Think about 3,200 people,” said Michael Keck, who worked at the Ford factory for 33 years and is a United Auto Workers (UAW) official. “Probably 2,000 or more of them living in this community, spending money in this community. Gone. Some of them may still live here but they work in Dearborn or Flat Rock. So that’s where they spend their money. The impact was huge.”

Industries have come and gone from Monroe before. More than a dozen paper mills that once employed thousands making corrugated cardboard boxes were mostly closed by the 1970s. Some of the workers found jobs at the new Ford plant, which became Monroe’s largest employer.

When that went too, just as the national recession hit, home foreclosures surged. Some people walked away from their houses. Others were locked out by the banks.

Monroe struggled as shops went to the wall. The local mall is a shell of its once bustling self after major stores such as Sears and Target abandoned it.

Some industrial jobs remain in steel and at a nuclear power plant. But those forced to find work elsewhere in the county frequently took cuts in pay as they shifted to non-unionised jobs in healthcare, which, like many other struggling parts of the midwest, provides an increasing proportion of employment.

With the national economic shock of the recession and the local impact of the Ford closure, the majority white county began its shift away from longstanding support for the Democrats by electing Republicans to local and state offices even if voters also backed Obama. In those circumstances, the move from Obama to Trump does not look quite so jarring.

Keck, who worked in the Ford factory, thinks it was at least in part an act of desperation by those disappointed that Obama did not make the dramatic changes his historic election promised.

To some, Obama seemed more interested in looking after the banks more than unemployed workers struggling to pay their mortgages. Clinton represented more of the same in 2016.

The UAW ordered Keck to campaign for her even though he was at heart a Bernie Sanders supporter. Three years later he remains bitter at what he regards as Clinton’s out-of-touch campaign.

Against that, Trump appeared to be listening to people in Monroe county.

The anger that burst out at the ballot box in 2016 has only escalated. Some of it comes from Trump supporters horrified at what he has become.

Then there are those such as construction boss Misty Kendall, who voted for Trump less as a statement of support than in opposition to Clinton and who now regard criticism of the president as a personal attack on them. That has helped solidify support for the president among those prepared to set aside his sins, personal and political.

A few will defend his tweets and diminishing the dignity of his office as evidence that he is standing up to the elites and telling it like it is.

Kendall is prepared to acknowledge criticism of Trump’s language, calling him “kind of crass”. But she regards much of what exercises the president’s critics, from migrant detentions to his climate policies, as faux concerns fabricated as a means to attack him.

“Everybody gets so offended if you’re a Trump supporter,” said Kendall. “I just wish that everybody had a more open mind about the situation. We don’t all have to agree. I think he’s a great president. He’s my president. If a Democrat gets elected, guess what? It’s still my president. I might not like it but I have to abide by it because I’m an American.”

Healthcare: a huge issue

On the other side, anger at Clinton on the Democratic party’s left in 2016, which led some voters to stay away, has turned on Trump and fuelled a surge in activism and engagement with the primaries.

The challenge for the party in places such as Monroe county is to find the crossover issues to lure at least some Trump voters back and get wavering voters to the polls.

For some, the best issue may be the one which proved most damaging to Obama among many voters – healthcare reform.

“People were not happy with Obamacare around here when it raised the cost. This isn’t a wealthy area,” said LaVoy, the former Democratic state representative. “But health care needs to be fixed. That’s something Trump ran on and he didn’t do it. It’s an opportunity.”

Jeff Morris, the president of the local UAW branch, who has worked for 29 years at the Gerdau steel mill in Monroe, said it is the primary political issue for most of his members.

“Healthcare for my 500 members is huge. They ask if a candidate is gonna fix healthcare. That’s the whole nine yards,” he said.

The challenge for the Democratic party in counties such as Monroe is to present a policy such as healthcare reform that can win back some working class voters and mobilise the young without scaring off other voters with charges of socialism or government overreach.

‘Now we’re scared’

Part of the challenge is to keep the political debate focused on policies such as healthcare as the president works to get Americans to look elsewhere.

“In the 80s, when I was growing up, it was always abortion and guns,” said Morris. “There’s a version of that going on right now with immigration. It’s a huge distraction and it’s intentional.”

And it works. Ask what the president is getting right and Kendall vigorously defends his immigration policies as preventing a flood of people across the border to live on her taxes. She disparages reports of separation of families on the border as political propaganda.

Against that, LaVoy looked on in alarm at the Democratic primary debates as candidates batted around proposals to weaken border controls or ease restrictions on asylum applications – “open borders”, as Trump characterises it. LaVoy regards the debate as a quagmire that will suck the party down.

“The immigration stuff, this county is 90% white. That doesn’t play well around here,” he said. “The Democratic party should be careful because if Trump wins Michigan, he wins the presidency because that means not much has changed in the midwest.”

At the fair, a Democratic activist, Yvonne Morrison, is certain that Trump’s framing of immigration is working for him. “This terrible resentment has bubbled up like a cesspool,” she said. “Last time we laughed at Trump. Now we’re scared. I think he’ll win again. His support hasn’t moved an inch.”