Republican Matt Van Epps will become the next congressman from Tennessee’s seventh district after winning his race on Tuesday night. His party, however, may find little comfort in his single-digit win after President Trump won the same district by more than 20 points last year. 

Mr. Van Epps was declared the winner of the race a little over an hour after polls closed Tuesday night. He is currently on track to win the race by around nine points after both Democrats and Republicans spent millions of dollars on the two campaigns. 

Ms. Behn, a liberal state representative, won the support of national Democrats from across the ideological spectrum. The night before the election, Vice President Al Gore and Congresswoman Alexandria Ocasio-Cortez held a video conference rally for thousands of Ms. Behn’s supporters. 

“It’s very, very exciting,” Mr. Gore, who represented Tennessee in Congress for 16 years before being elected vice president, said of the race on Monday night. “I have never seen the political tides shift as far and as fast as we’re seeing them move in this election.”

Ms. Behn was no moderate in the race, despite her ability to compete in her deep-red district. She is a supporter of universal health care, an unabashed defender of transgender rights, and an outspoken advocate for slashing police budgets. 

The seat became vacant over the summer after Congressman Mark Green resigned to pursue opportunities in the private sector. Though initially the race to replace Mr. Green was seen as a guaranteed victory for Republicans, the GOP had to spend millions of dollars to get Mr. Van Epps over the finish line. Democrats, too, spent millions, though the GOP invested more money in the race than their opponents. 

In total, both parties spent more than $7 million on this special election. 

Despite the win, Speaker Mike Johnson’s life is not likely to get much easier. His majority will now climb to 220 members, though Democrats will win a deep-blue district in Texas in just a few weeks, bringing the minority party’s caucus up to 214 members. On party-line votes, Mr. Johnson will be able to lose just two of his Republican colleagues if he wants to pass any measure. 

That margin will only get worse in January when Congresswoman Marjorie Taylor Greene officially resigns. She says that she is quitting politics because of the nastiness and the inability of her Republican colleagues to deliver on their 2024 campaign promises. She will leave office on January 5. 

“We have this joke that I’m not really a speaker of the House,” Mr. Johnson told conservative podcaster Katie Miller last week. Ms. Miller is married to top White House aide Stephen Miller. 

“We’re in triage every day, and every day is different. There’s no pattern or schedule,” the speaker, who did the joint interview with his wife Kelly Johnson, said. “We’re kind of in survival mode right now. We order in food because we just don’t have the time or luxury of cooking.”

Despite their defeat on Tuesday, Democrats have little to worry about after the 13-point swing of Tennessee’s seventh district in the special election. 

If Democrats can replicate their 13-point overperformance on Tuesday night in the midterm elections next year, several Republicans in safe red districts will be in trouble. As of this writing, there are dozens of Republicans serving in districts Mr. Trump won by 13 points or less who are planning on running for re-election next year. If the Tennessee seventh district’s margin becomes Democrats’ real swing in the 2026 elections, they will pick up several seats in Arizona, New York, and Pennsylvania, to name just a few.