Democrats are taking a bold gamble deep in the heart of Tennessee’s so-called MAGA country, hoping for a stunning upset in a special congressional election that could shake up the House and send shockwaves through Donald Trump’s Republican base.

The high-stakes contest—happening Tuesday—comes after GOP Congressman Mark Green abruptly quit his seat in July, leaving Tennessee’s heavily conservative 7th District up for grabs. Republican bigwigs carved these district lines to deliver slam-dunk victories for their side, and just last year both Trump and Green stomped their opponents by a whopping 22-point margin.

Enter Matt Van Epps, the Republican hopeful, who in any other year would be a near-lock for Congress. But after Democrats recently snatched victories from Republicans in states like Virginia and New Jersey, party leaders in D.C. started smelling blood in the water. Energized by momentum, national Democrats are throwing cash and star power behind state representative Aftyn Behn, betting on an electoral shocker that would strike fear into Trump’s allies.

And there’s reason for GOP nerves: A fresh Emerson College Polling/The Hill survey released Wednesday shows Van Epps barely ahead—just two points above Behn, with 48% to her 46%. Suddenly, this safe red seat looks more like a battleground than a coronation.

The sprawling district runs from Kentucky down to Alabama and carves through rural stretches where Republican dominance is the norm. Yet, it also includes slices of Nashville’s Democratic stronghold and Clarksville—a swing city that just might tip the scales come election night. Black voters account for about 15% of the population here, and according to Cook Political Report’s Dave Wasserman, their turnout is crucial for Behn’s longshot hopes. Still, Black voter turnout is notoriously unpredictable, keeping political strategists on both sides biting their nails.

“The Republicans have the edge, but it could be a nail-biter,” Wasserman predicted. Meanwhile, Kent Syler, a Middle Tennessee State University professor and ex-aide to Democratic Rep. Bart Gordon, warned that, “It’s a Republican district, no question, but the Democrats are fired up—Republicans ignore that at their peril.”

If Behn pulls off a win, it would obliterate the GOP’s slim House advantage, opening a path for Democrats to seize the majority before next year’s midterms—especially if one or two more Republicans bail. The GOP was rocked recently when Trump confidant Marjorie Taylor Greene called it quits amid tensions with the former president, signaling churn and chaos within Republican ranks.

Adding fuel to the fire, heavy-hitting Democratic PACs—like the House Majority PAC—have shelled out $1 million in digital and TV ads to help propel Behn past the post. Their message is clear: No Republican seat is off limits, and the battle for Congress is on like never before.