Originally Published: September 2, 2024 8:00 a.m.

For Democrats to maintain Senate control, Senator Jon Tester (D-MT) needs to win reelection in a state Donald Trump won by 16.4 percentage points in 2020. 

That brutal reality is reflective of the vicious Senate map Democrats were handed this year in a chamber already tilted against them. After Sen. Joe Manchin's (D-WV) retirement, Republicans can confidently add that seat to their roster, bringing them to 50 senators, assuming they return their incumbents (whose losses would be major upsets). Tester's loss would give them the majority.

If Tester wins, and Democrats win the White House and flip the House, that means a 2020-like environment with the possibility of major legislation and the certainty of judicial confirmations. If he does not, Congress would return to 2022's legislative graveyard, now with a Republican Senate that would likely block many judicial confirmations and move to stop a President Kamala Harris from filling any Supreme Court vacancies that arise. If Republicans win the presidency and keep the House, of course, Democrats' losing the Senate opens the door to a no-holds-barred, full-scale Trump agenda. 

The perennial survivor, the last statewide Democrat in an increasingly MAGAfied Montana, has to turn in the political performance of a lifetime, and do something he's never done before — overcome those headwinds in an election where Trump is on the ballot.

"Oh yes," Mike Dennison, currently a political analyst and the former longtime chief political reporter at the Montana Television Network, said when TPM asked if Tester could win in these conditions. "Although it'll probably be the most difficult test in his career."

Tester is now a singular breed in the Senate, the last stronghold in a state that has, particularly in the past four years, completely repudiated his party. Sens. Sherrod Brown (D-OH) — also in the fight of his life — and Susan Collins (R-ME) have historically pulled off a similar feat, but still operate in more hospitable environments than Tester. In 2018, the other Tester-like incumbents in the Senate — Democrats Joe Donnelly in Indiana, Claire McCaskill in Missouri, Heidi Heitkamp in North Dakota — got wiped out, presaging the death of ticket-splitting among an increasingly polarized electorate. Tester hung on by 3.6 points. 

Now, Tester finds himself in a curious moment. President Joe Biden, whose drag Tester felt acutely enough to publicly beseech him to leave the race, has done so. Democrats have a new nominee in Vice President Kamala Harris, bringing with her an exuberant and newly generous voting base.