Sen. Joe Manchin (D-W.Va.) announced Thursday that he will not seek reelection to the Senate in 2024, almost certainly handing Republicans a seat in next year’s elections in a deep red state.

“After months of deliberation and long conversations with my family, I believe in my heart of hearts that I have accomplished what I set out to do for West Virginia. I have made one of the toughest decisions of my life and decided that I will not be running for re-election to the United States Senate,” Manchin, 76, said in a statement. “But what I will be doing is traveling the country and speaking out to see if there is an interest in creating a movement to mobilize the middle and bring Americans together.”

Manchin, who has held his seat since 2010, had long been considered the most vulnerable Senate Democrat on the map heading into 2024 and was, until Thursday, the lone Democratic incumbent who hadn’t made his 2024 plans public. His announcement had been expected later this year or closer to the January filing deadline. 

He was staring down the toughest electoral challenge of his Senatorial career, as West Virginia Gov. Jim Justice (R) has increasingly become the favorite to win next year.

“Senator Joe Manchin and I have not always agreed on policy and politics, but we’re both lifelong West Virginians who love this state beyond belief, and I respect and thank him for his many years of public service,” Justice said Thursday.

Democrats have said throughout the past year that Manchin is the only member of their party to have a shot of winning in the ruby red state, and the seat will now almost certainly fall into GOP hands.

Former President Trump carried West Virginia in 2020 by 39 percentage points. Manchin, a former West Virginia governor, won his 2018 reelection contest over West Virginia Attorney General Patrick Morrisey (R) by more than 3 percentage points. 

“We head into the election with a 50-50 Senate,” one Senate Republican aide said, adding that it is a “huge” development. 

The National Republican Senatorial Committee (NRSC) also indicated its happiness with Manchin’s decision. The NRSC has endorsed Justice in the race over Rep. Alex Mooney (R-W.Va.), the favorite of conservatives and the Club for Growth.

“We like our odds in West Virginia,” Sen. Steve Daines (R-Mont.), the NRSC chair, said in a statement. 

The Senate Democratic campaign arm argued that it still has ways to keep control of the chamber. 

“Democrats have multiple pathways to protect and strengthen our Senate majority and are in a strong position to achieve this goal,” David Bergstein, a Democratic Senatorial Campaign Committee spokesman, said in a statement, arguing that seats occupied by Sens. Rick Scott (R-Fla.) and Ted Cruz (R-Texas) are in play.

“We’ve already expanded the battleground map to Texas and Florida, where formidable Democratic candidates are out-raising unpopular Republican incumbents,” Bergstein added. 

With the West Virginia race shaping up well for Republicans, all eyes will now shift even more to Montana and Ohio, two states in red terrain featuring strong Democratic incumbents in Sens. Jon Tester (Mont.) and Sherrod Brown (Ohio). 

Republicans have also looked for opportunities to pick off other states in which they’ve been competitive in recent years, including Wisconsin, Pennsylvania, Arizona, Nevada and Michigan.

Manchin’s decision leaves a major void in the center of the Senate. He has been at the center of bipartisan negotiations of many stripes in recent years and has been widely considered the most moderate member of the Senate Democratic caucus, with questions persisting throughout whether he could leave the party, especially after Sen. Kyrsten Sinema (I-Ariz.) did so late last year. 

However, he’d also earned the derision of voters back home with his support for the Inflation Reduction Act last year, having previously thwarted the effort by President Biden and Senate Democrats to pass the Build Back Better agenda, a multi-trillion-dollar social spending package.

“I think we need more Democrats like him,” Sen. Chuck Grassley (R-Iowa) told The Hill, adding that while another Republican will likely occupy the seat after next year, more Democrats of Manchin’s ilk are needed. “It doesn’t mean that I particularly want to see people like Manchin leave the Senate if they’re Democrats that work in a bipartisan say. We need more of that. We had enough partisan votes the last two years anyway, and we would have had a lot more if he and Sinema had not been very independent.”

Questions now will shift to Manchin’s future plans. He has notably declined to tamp down chatter of a potential No Labels independent presidential bid, having visited New Hampshire for an event by the group over the summer.  

“Every incentive in Washington is designed to make our politics extreme. The growing divide between Democrats and Republicans is paralyzing Congress and worsening our nation’s problems,” Manchin said in his statement. “The majority of Americans are just plain worn out.”

“I know our country isn’t as divided as Washington wants us to believe. We share common values of family, freedom, democracy, dignity and a belief that together we can overcome any challenge,” he said. “We need to take back America and not let this divisive hatred further pull us apart.”

Aris Folley contributed. Updated at 3:57 p.m. ET