But Tester’s decision, along with Sen. Sherrod Brown’s (D-Ohio) bid for a fourth term, gives Democrats a pathway to keep their majority. The party currently holds 51 seats, meaning it can only afford a net loss of one seat in 2024 provided Democrats maintain control of the White House. And with sparse pick-up opportunities next year, the most straightforward path is returning the party’s incumbents to office, meaning Democrats must win reelection in at least two of the three red states: Ohio, West Virginia and Montana.

Tester has won races under myriad scenarios since entering national politics. He defeated former GOP Sen. Conrad Burns in 2006, successfully split tickets with former President Barack Obama in 2012 and survived a difficult midterm cycle in 2018 by defeating now-Rep. Matt Rosendale (R-Mont.). During that race, Tester raised the ire of former President Donald Trump by helping sink his pick for the Veterans’ Affairs Department, now-Rep. Ronny Jackson (R-Texas).

Both Rosendale and Rep. Ryan Zinke (R-Mont.) are weighing a bid against Tester; Zinke passed on the 2018 race by joining Trump’s cabinet as secretary of the Interior. Republicans are also keeping their eyes on Gov. Greg Gianforte and state Attorney General Austin Knudsen to mount potential GOP campaigns to unseat Tester.

Sen. Steve Daines (R-Mont.) is chairing the GOP campaign arm this cycle, adding intrigue to Tester’s bid after Tester helped recruit former Montana Gov. Steve Bullock, a Democrat, to run against Daines in 2020. Daines campaigned with Rosendale in the fall of 2018 as the GOP pressed to beat Tester, albeit unsuccessfully.

“Jon Tester just made the same mistake Steve Bullock did in 2020. Both should have ended their political careers on their terms. Instead, they each will have their careers ended by Montana voters,” Daines said in a statement on Wednesday afternoon.

The Montana Democrat, who chairs the Senate Veterans’ Affairs Committee, is known for working across the aisle and played a key role in negotiating the Senate’s bipartisan infrastructure bill last Congress. He also teamed up with Sen. Jerry Moran (R-Kan.) to pass legislation that broadened the Department of Veterans’ Affairs coverage for toxic exposure related to burn pits.

Tester has a more liberal voting record than Manchin but a more centrist one than Brown. He did not serve as a public roadblock to President Joe Biden’s agenda like Manchin and Sen. Kyrsten Sinema (I-Ariz.), though he does occasionally vote against the party leadership, like on a bid to raise the minimum wage to $15. More recently, he criticized the Biden administration over its handling of a Chinese government spy balloon that flew over Montana.

Tester also has a unique personal profile: He’s a working farmer who lost three fingers in a meat grinder as a child and is known in Washington and Montana for blunt talk and the occasional expletive. His political skills will be put to the test, though, as Montana grew significantly during the pandemic, meaning he will face thousands of new voters next November.

While Tester has yet to announce his campaign team, his 2018 campaign manager Christie Roberts is expected to stay on for another consecutive cycle at the Democratic Senate campaign arm in a senior role.