Republicans are all but sure to pick up a new Senate seat in ruby-red West Virginia next year with Sen. Joe Manchin’s retirement ringing like a death knell for Democrats’ presence in state-wide offices there. 

Manchin’s Thursday announcement sent shock waves through Capitol Hill, but it is not the first time he has dealt a blow to his own party — particularly in recent years under President Biden. 

The conservative Democrat announced in December 2021 that he would not support Biden’s $2.2 trillion progressive Build Back Better package, effectively sinking the left-wing wish list. 

It invoked the ire of progressives like Rep. Alexandria Ocasio-Cortez, D-N.Y., who attacked Manchin for forcing Democrats to decouple the package from a more moderate bipartisan infrastructure proposal. 

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Joe Manchin

Sen. Joe Manchin is not seeking re-election in the Senate.

"When a handful of us in the House warned this would happen if Dem leaders gave Manchin everything he wanted 1st by moving [infrastructure] before BBB instead of passing together, many ridiculed our position. Maybe they’ll believe us next time. Or maybe people will just keep calling us naïve," she wrote on X at the time. 

Manchin’s support for Biden’s policies plummeted over the course of his administration as well. A report from polling aggregation site FiveThirtyEight found that Manchin voted with Biden’s position roughly 21% of the time during this Congress.

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Republicans are now confident that Manchin has handed them a victory over Democrats with his announcement that he will not run again in 2024, in a state that overwhelmingly voted for former President Trump in both 2016 and 2020. 

National Republican Senatorial Committee (NRSC) Chair Steve Daines, R-Mont., released a simple statement on the news, "We like our odds in West Virginia."

President Joe Biden

Sen. Joe Manchin only voted with President Biden about 21% of the time during his Congress. (The Image Direct for Fox News Digital)

"When a party committee puts out a one-sentence statement, they’re telling you very bluntly how they assess the situation," GOP strategist Doug Heye told Fox News Digital on Friday. "Clearly, the NRSC believes [Manchin’s] retirement makes this a very, very safe seat for Republicans now."

While it could very well help Democrats lose the Senate majority, Republicans now likely just need to flip one more vulnerable Democratic seat to win. Democrats have already lacked a reliable vote in Manchin on some of Biden’s more progressive nominees.

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This past May, Manchin vowed to oppose all of Biden’s nominees to the Environmental Protection Agency, citing the administration’s "commitment to their extreme ideology," which he said "overshadows their responsibility to ensure long-lasting energy and economic security."

Steve Daines

Sen. Steve Daines was among the Republicans buoyant over Sen. Joe Manchin's announcement. (Drew Angerer/Getty Images)

He also derailed acting Labor Secretary Julie Su’s nomination to Biden’s Cabinet.

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What Manchin does next is not immediately clear, but he could further pose problems for the Democratic Party down the line — his pledge to "unite the middle" in his Thursday announcement raised eyebrows whether he will challenge Biden for the White House.

"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 said. "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."