"They're coming to Tennessee to try to take a congressional seat."

Tennessee Republican Party Chair Scott Golden offered this warning to party faithful last week at the Cumberland County Lincoln Day Dinner in the tiny town of Crab Orchard.

Over a dinner of turkey, ham and mashed potatoes, and after a keynote speech by an actual Abraham Lincoln impersonator, Golden noted that a 2 December special election to fill an open congressional seat has put his state at the centre of the American political universe - Democratic resources are pouring in.

Earlier this month, the Democratic Party chair held a rally in the district. And last Tuesday, former Vice-President Kamala Harris visited campaign workers at a canvassing event.

"Why am I in Tennessee?" she asked the crowd. "Because I know the power is in the South."

The district at issue should be reliably conservative. Donald Trump won there by 22 percentage points in last year's presidential election. But both Republicans and Democrats are acting like the race is much closer - and political forecasters agree.

"Sources roundly agree that Nashville Democrats are ravenous at the prospect of an upset, while many Republican voters are unaware an election is even taking place," writes Matthew Klein of the Cook Political Report.

The election comes as cracks have appeared in Trump's grip over his party on a number of issues - culminating in conservative firebrand Marjorie Taylor Greene's surprise resignation from Congress on Friday night.

"No matter which way the political pendulum swings, Republican or Democrat, nothing ever gets better for the common American man or woman," she said in her resignation speech.

The outcome in Tennessee alone won't flip control of the closely divided House of Representatives. But a Republican loss could prompt a panic within party ranks at a time when Trump is vulnerable and many conservatives are glancing nervously at next year's midterm congressional elections.

The results could also reveal a shifting political landscape even in the heart of Trump country – and hint at how the Republican Party is slowly coming to grips with a world after Trump.

"Republicans are going to have to start thinking about the future," said John Geer, a political science professor at Nashville's Vanderbilt University. "It's going to be hard to do, but at a certain point they're going to see it in their electoral interests."

Tennessee voters are casting ballots less than a month after local elections earlier this month saw a shift towards Democratic candidates running on the economy.

Since then, Republicans, including Trump, have been scrambling to reshape their message to focus on "affordability" – the label Democrats have applied to concerns about high consumer prices and a rising cost of living.

The president has cut tariffs on grocery items like coffee, bananas, beef and avocados. He has proposed 50-year mortgages and $2,000 tariff rebates to low- and middle- income Americans. But it hasn't been a smooth process, and there have been some signs that Trump's Make America Great Again – Maga – coalition is fraying.

During an interview on Fox News last week, Trump sparred with presenter Laura Ingraham over the mortgage proposal, which some conservatives believe will only line the pockets of big banks.

She also echoed conservative concerns about his support of H1-B visas for foreign workers - which Trump defended as necessary because Americans sometimes lacked "certain talents".

On the ground in Tennessee, as it was in recent elections in Virginia and Pennsylvania, bread-and-butter economic issues dominated the conversation.

Even here, however, there is evidence of conservative dissatisfaction.

A recent national poll conducted by Vanderbilt University found that more than 60% of Trump supporters "disagreed" with the notion that the cost of living had decreased over the past year.

The national mood, when it comes to inflation, cost of living and the economy, is "very sour", said Professor Greer, who is co-director of the Vanderbilt poll.

"There's genuine unhappiness, partly because Trump made prices an issue," Geer noted. "He said he was going to bring them down, and he hasn't."

Tennessee is still decidedly Trump terrain. He won the state with 64% of the vote last year and topped 60% the previous two presidential elections. But even here, Republicans appear to be feeling out how to adjust to a changing political environment – one in which the economy is a political liability, as opposed to a means to attack incumbent Democrats.

The Democratic nominee, state legislator Aftyn Behn, has focused almost exclusively on affordability and local quality of life issues. Her yard signs read: "Feed kids, fix roads, fund hospitals".

Her television adverts hit her Republican opponent, Matt Van Epps, for his ties to Washington Republicans, including Speaker of the House Mike Johnson of Louisiana.

"This campaign has been one about building a coalition of the disenchanted, a coalition of the pissed off," she told the BBC during an organising event in Nashville last week. "If you're upset about the chaos in Washington, if you're upset about the cost of living, then I'm your candidate."

Van Epps, in style and substance, is a typical modern Republican candidate. An Army pilot, he served nine tours of duty in Iraq and Afghanistan. His yard sign sports the outline of a Chinook helicopter, the kind he flew on special operations missions.

He ran in a crowded primary where loyalty to Trump was a litmus test – and a last-minute endorsement by the president put him over the top.

But Van Epps's general election campaign has been a marked contrast. While he held a 20-minute tele-rally with Trump two weeks ago, the candidate doesn't talk about the president much on the campaign trail. Like Behn - and unlike recent Republicans - his advertising hones in on economic, not cultural issues.

The Van Epps campaign did not respond to BBC requests for an interview, but his comments on local television struck a familiar theme.

"I think we are moving in a great direction, but we've got work to do," he said. "The cost of living is too high; inflation is still too high."

The campaign underscores a new reality. While Trump's ballot-box power is unmistakable, his ability to help his fellow Republicans prevail when his name is not on the ballot alongside them is suspect.

Republicans were drubbed in the 2018 midterms. They underperformed expectations in 2022. They were roundly beaten earlier this month. And barring an arduous constitutional change to remove presidential term limits, Trump's name is never again going to be at the top of the Republican ticket.

For Republicans, the future after Trump is starting now.

A Democratic win here in Tennessee next month would be seismic. It could force Republicans to grapple more fully with the costs of sticking with Trump when he is not on the ballot. And it might exacerbate fault lines that are already starting to show within the party.

Even without such an upset, however, those fault lines are becoming apparent in Washington DC, where Republicans like Greene have become increasingly critical of some of the president's policies – on healthcare, the economy and foreign affairs.

She helped spearhead an effort to force a vote on releasing the Epstein files despite strong opposition from Trump's White House

Back at the Republican dinner in Crab Orchard, the Epstein vote happening the same day was absent from the evening's public remarks.

When asked, however, many present acknowledged that the issue of Epstein was important to their constituents – and expressed hope that the vote would allow the party to return focus to other issues.

"The Epstein files need to be in the rear view mirror," said Chelsea Rose, who was standing in for her husband, Congressman John Rose, who had stayed back in Washington for the Epstein vote. "Frankly, it's been a distraction for a long time now, and I'm glad for it to be behind us.

As for the party divisions on display in Washington, some were more circumspect.

"We support Donald Trump here, and we appreciate what he's doing," said Van Hilleary, who represented Tennessee in the House from 1995 to 2003 and is now running for his old seat.

The challenge for Trump, he continued, is that the measures that he has taken may cause some short-term disruptions and discomfort.

"We've let this thing go so long that the pretty fixes are in a rear view mirror," he said. "I'm afraid what's in front of us are not very elegant, not very pretty fixes, but they have to be done."

The reality, however, is that Trump's sagging popularity, the consequences of some of his more disruptive policies – his "not very pretty fixes" and his focus on foreign policy - have put stress on the Republican coalition, even in conservative Tennessee.

The state's soy bean farmers and cattle ranchers have felt the pinch from tariffs and trade disputes. Looming expiration of health-insurance subsidies will hit low-income Tennesseans hard. And the state has seen the same stubbornly high consumer prices that have plagued the rest of the country.

That hasn't necessarily translated into a lack of support for Trump among his loyal voters in Tennessee, however.

"We've got this idea out here that everyone that supports Trump is this cult," Julia Timson, a schoolteacher who was at the Crab Orchard dinner said. "No. If he's wrong, he's wrong. But at the same time, I would say, I'm the champion in your corner."

Shane Wattenbarger, a construction contractor and longtime friend of Timson's, agreed.

"I think he's just a flat-out arrogant prick," he said of Trump. "But for this country, that's what it needs."

Trump's electoral magic has been his ability to attract new, disaffected voters while keeping longtime Republicans – even those who think he's arrogant, coarse or wrongheaded at times – in the fold.

In Tennessee, that magic may still be enough to pull the Republican candidate over the finish line. Democrats have had high hopes in the past about special-election surprises on conservative territory only to come up short. But even here, the political ground may be shifting.

"One of the things that has been common over elections over the last decade is the people have wanted change every time," said Geer. "And so if you want change right now, you'd vote for someone like Aftyn Behn." (BBC)