It could be days — or even weeks — before Americans know who will control the House of Representatives in the next Congress, setting up what could be a long and anxious window of uncertainty surrounding the balance of power on Capitol Hill next year.

There are dozens of closely contested seats up for grabs, setting the stage for a potential scenario where many of those contests are too close to call on election night and the race to 218 remains unresolved.

Determining the ultimate winner in that situation will almost certainly take days — or longer —  as late ballots filter in, slow-counting states tally their results and likely legal challenges work their way through the courts.

Such an ambiguous outcome would complicate not only the legislative work Congress has on deck to tackle in the postelection lame duck session, but also the leadership landscape in the next Congress. That’s particularly true on the Republican side, where Speaker Mike Johnson (R-La.) faces an uncertain future, particularly in a GOP minority, due to opposition from conservatives in his conference. 

Democrats need to pick up four seats to win control of the House, and election analysts and operatives in both parties expect that, regardless of who prevails, the final breakdown will be close.

“The days of a 230, 240 majority are gone,” a GOP strategist familiar with House races said, noting that redistricting has cut down on the number of truly competitive seats. “So, it’s going to be a small majority for whoever wins.”

“Days or weeks is entirely possible,” another GOP strategist said of how long it will take to know control of the House. 

Republicans are not the only party bracing for long days of uncertainty. Democrats are quick to point out that the GOP's current House majority hinged on 2022 victories in the five closest races where the combined Republican victory added up to fewer than 7,000 votes.

"There is every reason to believe that, at least in general terms across the country, it will probably be that close again,” said a Democratic strategist familiar with House races. “There are only so many purple districts left, and in those purple districts — boy, are they really purple. The margins are very, very narrow."

It would not be the first time the House was left in postelection limbo because of tight races. In 2022, the Associated Press did not officially determine that Republicans won the House majority until more than a week after Election Day.

That year, results from California proved both crucial and late-arriving, and election watchers are expecting a similar dynamic.

“The big question mark is California. We’re kind of counting on not knowing a lot of the results in California maybe until, like, the week of Thanksgiving. They just take forever to count,” the first GOP strategist said.

Six of the 15 districts rated as toss-ups in an analysis by Decision Desk HQ/The Hill are in California, including seats held by GOP incumbent Reps. John Duarte, Mike Garcia, Ken Calvert, and David Valadao.

Mail-in ballots are what can keep California’s competitive races in suspense. The Golden State counts mail-in ballots that were postmarked by Election Day and received as late as seven days after the election.

“Everyone should keep in mind John Duarte’s race was called on Dec. 2, 2022 — almost a month after Election Day,” the second GOP strategist said.

California is hardly alone. 

Washington and Oregon, which are both home to battleground House districts that are expected to come down to the wire, operate exclusively under mail-in voting systems that also require that ballots be only postmarked — not received — by Election Day. That means it could take days for the results to be known in the race for Oregon’s 5th District, where GOP Rep. Lori Chavez-DeRemer is fighting for reelection, and Washington’s 3rd District, where Democratic Rep. Marie Gluesenkamp Perez is hoping to hang on for a second term. The Cook Political Report ranks both races a “toss-up.”

Pennsylvania does not have exclusive mail-in voting, but experts say the state’s election rules, which prohibit election workers from processing those ballots before Election Day, are likely to lead to delays in the results, not least because of the three House incumbents — Reps. Matt Cartwright (D), Susan Wild (D) and Scott Perry (R) — all in toss-up races. 

Experts say even some of the fastest-counting states aren’t immune to potential delays. Contested seats in Virginia, Iowa and Michigan, for instance, could be too close to call immediately, leaving as many as six races unresolved before voters go to bed on Tuesday. Those include the contest to fill the open seat vacated by Democratic Rep. Abigail Spanberger (D-Va.), who is retiring to run for governor, and the fight for Iowa’s 1st District, where GOP Rep. Mariannette Miller-Meeks is a top Democratic target. 

“I don't think any of us would be surprised if we didn't have declared winners in Virginia and Iowa on election night,” the Democratic strategist said. “That's how close, generally, the whole map is."

The dynamic raises questions about how Republicans, in particular, may handle the uncertainty amid looming leadership elections. The internal contest is scheduled for Nov. 13, the Wednesday after the election when Congress returns to Washington, according to sources familiar with the schedule.

While the House Democrats are expected to have the same leadership team no matter who wins the election — with Hakeem Jeffries (D-N.Y.) either staying minority leader or moving up to Speaker — House Republicans are bracing for potential leadership shake-ups after the election, especially if Democrats take control of the lower chamber.

Johnson has repeatedly declined to say whether he would seek to be minority leader if that happens. 

House Majority Leader Steve Scalise (R-La.) is the current No. 2 House Republican, but some members suspect Rep. Jim Jordan (R-Ohio) could make a play for the minority leader slot. The Freedom Caucus co-founder and House Judiciary chair has been noticeably increasing his efforts to help GOP members across ideological lines on the campaign trail this cycle, and he has not directly said he would not seek the Minority Leader slot.

But if party control is uncertain, that could affect who seeks leadership positions, or who members want to support.

Rep. Marjorie Taylor Greene (R-Ga.), a critic of Johnson, has called to delay the House GOP’s leadership elections because of that uncertainty.

“Leadership races should not be rushed for political gain,” Greene posted Friday on the social platform X, adding: “This date should be pushed back.”

Rep. Thomas Massie (R-Ky.), who joined Greene’s unsuccessful effort to oust Johnson from the Speakership earlier this year, reposted Green’s post on X.

In 2022, House Republicans held their internal leadership election despite not officially having 218 seats called in their favor, but the dynamics that year looked much more favorable to Republicans — even though they underperformed expectations.

Johnson, in an interview with The Hill from the campaign trail in Pennsylvania last week, declined to say whether the House GOP would delay elections if House control is unknown.

“We’ll cross that bridge when we come to it,” Johnson said.