Today is a very good day for Senate Democrats

On Montana.

There are decisions made months and months before an election that have the potential to swing that election.

This, from Montana Democratic Sen. Jon Tester today, was one of them:

It's official. I'm running for reelection. Montanans need a fighter that will hold our government accountable and demand Washington stand up for veterans and lower costs for families. I will always fight to defend our Montana values. Let's get to work.

Tester had been publicly on the fence about running for a 4th term next November and, had he decided not to run, his seat would have been a near-certain Republican pickup.

Montana went for Donald Trump by 16 points in 2020 and Tester is the only Democrat who currently holds statewide office.

Tester’s decision to run is the first major piece of a decidedly complex puzzle for Democrats as they seek to upend expectations, again, and hold the Senate majority come 2025.

The math is decidedly against them. Democrats have to defend 23 of their own seats as compared to just 11 for Republicans. (Newly appointed Sen. Pete Ricketts will stand in an election in November 2024.)

Of the 23 seats Democrats are defending, three — Montana, Ohio and West Virginia — were won by Donald Trump won in 2020. (There are zero seats currently held by Republicans up in 2024 that Joe Biden won.)

Getting the incumbents to run in those three seats is of paramount importance if Democrats want to have any shot at keeping their majority.

Tester in now in. In Ohio, Sen. Sherrod Brown is running and running aggressively. (He’s already hired a campaign manager.) Which leaves Joe Manchin of West Virginia as the big question mark.

Manchin, asked Wednesday about whether he will run again, responded: “I don’t know.” (In that same interview, Manchin appeared to rule out running for president — only to rule it back in before the interview ended. Manchin!)

The question for Democrats is whether they can leverage the Tester announcement to help get Manchin to run again. While Montana would have been close to unwinnable without Tester, there is ZERO path to a victory in West Virginia for Democrats without Manchin. None.

Don’t underestimate momentum when it comes to this sort of stuff. Politicians, generally speaking, are a reactive bunch. They tend to put their finger in the wind to see which way it is blowing. And they look to what their colleagues are doing as a gauge for what they should be doing.

That doesn’t mean Manchin will run solely because Tester is. Manchin has always cut his own path, politically speaking, and clearly thinks of himself as one of one. But, there’s no question that Tester’s decision will reverberate into Manchin’s orbit in ways that Democrats have to believe are helpful.

Now, back to Montana.

Tester has never won with more than 50% of the vote. (He took 49% in 2006 and 2012 and 50% in 2018.)

Which means that whoever Republicans nominate has essentially a coin-flip chance of winning — and maybe better given that 2024 is a presidential year and should goose turnout across the state. (Tester did win reelection in 2012 even as Barack Obama was losing the state by 13 points to Mitt Romney.)

Who might that be? The two leading candidates appear to be the state’s two Members of Congress: Matt Rosendale and Ryan Zinke.

Rosendale, who was one of the last holdouts against Kevin McCarthy for Speaker earlier this year, was the Republican nominee against Tester back in 2018. He lost by 3 points while being heavily outspent.

Zinke served as Secretary of the Interior in the Trump Administration before being elected to Montana’s new congressional seat in 2022. At one time there were 18 federal investigations into Zinke’s time at Interior and the Department’s inspector general concluded that Zinke had misused his position and lied to investigators.

As you might guess, neither Zinke or Rosendale are regarded as “A” list candidates. And, some Republicans are pushing Gov. Greg Gianforte to consider the race. (In 2018, when Gianforte was running for Congress, he gained national attention when he body-slammed a reporter.)

Despite the flaws of their prospective candidates, Republicans are optimistic about their chances in Montana next November. It is , after all, a clear Republican state.

But, those hopes took at least a minor hit on Wednesday with Tester’s decision.

Tester is no sure thing. (No Democrat would be in Montana.) But he is a proven vote-getter in a state that hasn’t been hospitable to his party for the entirety of his political career.

In short: Democrats’ path to the Senate majority got a little wider today. And with a map as daunting as the party faces, they need every break they can get to have a chance at keeping their majority next November.