WASHINGTON —  The new Congress convenes Friday with one major task at hand — the election of the House speaker.

But current Speaker Mike Johnson’s weak grip on the gavel threatens not only his own survival but President-elect Donald Trump’s ambitious agenda of tax cuts and mass deportations as Republicans sweep to power in Washington.

With opposition from his own GOP colleagues, Johnson was holed up in the Capitol on the eve of the vote, working to sway the hard-line holdouts. A flop by Johnson could throw Monday’s congressional certification of Trump’s 2024 election victory into turmoil without a House speaker. Even backing from Trump himself, usually a sure bet for Republicans, is no guarantee Johnson will stay in power.

“I think he’s banking a lot on people liking him,” said Sarah Binder, a professor of political science at George Washington University.

“But you know I think we’re still down to: What does he need to give away in order to get the speakership? And then how long can he keep it?”

What was once a ceremonial day with newly elected lawmakers arriving to be sworn into office, often with family and friends in tow, has evolved into a high-stakes vote for the office of House speaker, among the most powerful elected positions in Washington.

While the Senate is able to convene on its own and has already elected party leaders — Sen. John Thune as the Republican majority leader and Sen. Chuck Schumer for the Democratic minority — the House must first elect its speaker, a role required by the Constitution, second in the line of succession to the president.

Congress has been here before, when it took Republicans nearly a week and 15 rounds of voting to elect Kevin McCarthy as speaker in 2023, a spectacle unseen in modern times. McCarthy was then dumped by his party, a historic first, but he was also part of a long list of GOP speakers chased to early exits.

The stakes are higher this year as Trump prepares to return to the White House with the House and Senate in GOP control and promising to deliver big on a 100-day agenda.

“He’s the one that can win right now,” Trump said about Johnson at a New Year’s Eve party that drew other GOP leaders to his Mar-a-Lago club in Florida.

Trump endorsed Johnson but also said “others are very good, too,” a nod to “Make America Great Again” allies in the president-elect’s orbit.

Johnson, of Louisiana, has been working diligently to prevent defeat, spending New Year’s Day at Mar-a-Lago as he positions himself alongside Trump. The speaker often portrays himself as the “quarterback” who will be executing the political plays called by the “coach,” the president-elect.

“We have to stay unified,” Johnson said on Fox Business late Thursday.

Johnson said he thinks he will lose perhaps only a single detractor, and hopes to win the speakership on the first round of balloting. He said he hasn’t yet asked Trump to make calls to the holdouts. “My conversations with my colleagues are going great.”

But Johnson also warned that without a House speaker there would be a “constitutional crisis” heading into Jan. 6, when Congress by law is required to count the electoral votes for president, weeks before Trump is set to be inaugurated Jan. 20.

“We don’t have any time to waste, and I think that everybody recognizes that,” he said.

Johnson commands one of the slimmest majorities in modern times, 220-215, having lost seats in the November election. That leaves him relying on almost every Republican for support in the face of Democratic opposition.

Heading into Friday he did not have the full support needed.

Texas GOP Rep. Chip Roy is among the most notable holdouts, an unflinching member of the Freedom Caucus who lashed into Republican leadership’s handling of the year-end spending bill for failing to cut spending and adhere to House rules.

“Something MUST change,” Roy posted on social media. He said he remains undecided on the speaker’s vote for Johnson, but added “my desire is to give him grace” in hopes they can deliver on the GOP agenda.

One almost certain hard no is Rep. Thomas Massie (R-Ky.), but other far-right Republicans, including some who helped topple McCarthy, have kept their views close.

“There’s a lot of discontent,” said Rep. Andy Biggs (R-Ariz.), as lawmakers left for the Christmas holiday.

What’s unclear is what other concessions Johnson can make to win support. Two years ago, McCarthy handed out prime favors that appeared to only weaken his hold on power.

Already, Johnson has clawed back one of those changes, with a new House rule pushed by centrist conservatives that would require at least nine members of the majority party on any resolution to oust the speaker — raising the threshold McCarthy had lowered to just one.

“I think the holdouts are going to have to realize that, listen, Trump is right all the time,” said Rep. Troy Nehls (R-Texas), exiting the speaker’s office late Thursday. “Just know that Trump is right all the time, it’ll help you make a decision real simple.”

Democrats expected to cast votes for party leader Hakeem Jeffries of New York.

Jeffries has said Democrats will not help save Johnson, as they have in the past with their votes when he faced a threat of removal.

Mascaro writes for the Associated Press.