By MARY CLARE JALONICK and STEPHEN GROVES

WASHINGTON (AP) — Republicans have elected South Dakota Sen. John Thune as the next Senate majority leader, completing a momentous shift in their leadership that elevates a top deputy of Mitch McConnell into a key position as President-elect Donald Trump returns to the White House.

Thune, 63, is in his fourth Senate term and has promised to work closely with Trump, despite differences the two have had over the years, and will be a crucial part of the incoming president’s efforts to push through his policy agenda.

In a statement, Thune said he was “extremely honored to have earned the support of my colleagues.”

“This Republican team is united behind President Trump’s agenda, and our work starts today,” he said.

Thune beat out two other competitors, Sens. John Cornyn and Rick Scott, by gaining majority support from GOP senators in a secret ballot vote in two rounds of voting. Scott was eliminated on the first round and the final vote between Thune and Cornyn was 29-24, according to several people who requested anonymity to discuss the private meeting.

Republicans are replacing McConnell, the longest serving Senate party leader, as they prepare to take majority control of the Senate with the 53 seats they won in last week’s elections.

Much of the campaign centered around the candidates relationship with Trump. Thune has worked to smooth his over after breaking publicly with Trump over the effort to overturn the results of the 2020 presidential election, which he called “inexcusable.”

In recent months, Thune has realigned with Trump, visiting him in his Florida home, and the two have been consulting on how to implement the incoming president’s agenda. Thune told The Associated Press over the summer that he views their potential relationship as a professional one. If they both win their elections, Thune said, “we’ve got a job to do.”

As he made his case, Thune also made clear that he would listen to Trumps demands. When Trump posted on X Sunday that the new leader “must agree” to allow him to appoint Cabinet members and others when the Senate is on recess, avoiding confirmation votes, Thune responded that the Senate must “quickly and decisively” act to get nominees in place and that “all options are on the table to make that happen, including recess appointments.”

Well liked and a respected communicator, Thune has been perceived as a front-runner for much of the year. Like McConnell, he hails from the Republican Party’s more traditional wing.

He is a former chairman of the Senate Commerce Committee and has held the Republican whip position — no. 2 in party leadership — since 2019. He took over for McConnell for several weeks last year when he was on a medical leave, a move that was widely seen as an audition of sorts as speculation surrounded McConnells future.

Thune’s win is all the more extraordinary because of his 2004 election to the Senate – defeating then-Senate Majority Leader Tom Daschle after arguing during the campaign that Daschle had lost his South Dakota roots during his years in Democratic leadership. Twenty years later, Thune will become majority leader himself.

As he geared up to run for leader, Thune spent much of the year campaigning for his colleagues. According to his aides, he raised more than $31 million to elect Senate Republicans this cycle, including a $4 million transfer from his own campaign accounts to the Senate’s main campaign arm.

The election was difficult for many in the conference who saw Thune and Cornyn as similar choices. They are alike on policy, voting generally in step with the conference but working with Democrats at times. Cornyn is a longtime member of the Senate Judiciary Committee who took a leading role on bipartisan gun legislation two years ago.

But the two differed on whether the leader should be term limited — a key demand from some in the conservative wing. Cornyn pushed for limits, while Thune did not.

Scott, the former governor of Florida, was elected to the Senate in 2018 and quickly positioned himself as a foil to McConnell, running against him for leader in 2022 and aligning with Utah Sen. Mike Lee and others who have been highly critical of the current leadership.

As Thune and Cornyn wooed their colleagues one by one all year, Scott spent most of the year tied up in his own reelection race. He handily defeated Democrat Debbie Mucarsel-Powell by more than 10 points.

After his re-election last week, Scott aggressively stepped up his campaign for GOP leader, campaigning publicly as the candidate closest to Trump and winning endorsements from people who are close to the former and future president, such as billionaire Elon Musk. But some questioned whether that strategy might backfire.

Rounds said that he prefers the way that Thune and Cornyn have “handled it one-on-one with everybody,” but that he had talked to Scott as well. “We’ve got three qualified individuals,” he said ahead of the race.