There was a time when it seemed like the Montana Senate race could have been the undercard in control for the Senate. Before West Virginia’s Democratic (now independent) Senator Joe Manchin announced he would not run for reelection this year, all-but-guaranteeing Republicans a seat pickup in the deep red state, it seemed like the most vulnerable Democrat was a conservative one with ties to the coal industry. Now, it’s Montana’s Jon Tester.

Tester has survived election and reelection for the last 18 years by virtue of two factors: running in Democratic-leaning or wave years and relying on his own reputation in a small state. In 2024, he’ll probably have to get by with just the latter. While 2006, 2012, and 2018 saw Democrats win national margins by 10.6%, 3.9% (in the presidential election), and 8.6%, respectively, 2024 doesn’t appear to be on track to match any of those numbers. This will be the second time Tester will be reliant on voters ticket-splitting between the presidential election and his own reelection, just as he was in 2012 (Mitt Romney carried the state by about 14%, while Tester won reelection by about 4%). In an era where heightened partisanship is making ticket-splitting increasingly rare, can Tester hold on?

His opponent, businessman Tim Sheehy, was something of national Republicans’ desired recruit. An ex-Navy SEAL, a millionaire, and someone with the backing of Donald Trump, Sheehy seemed like someone Republicans could feel comfortable with. However, he has proven to be less smooth and uncontroversial than hoped. He was taped delivering some racially-tinged remarks about the native Crow Indians. He has inflated or been murky about his own service record, including whether he shot himself in the arm or was instead shot in Afghanistan, and his business success isn’t as clean or clear as it seemed. This may give Tester a candidate quality advantage, much like he had six years ago against Matt Rosendale (there was actually some fear Rosendale may be the GOP’s nominee again this cycle; he ran for about a week before dropping out).

But, it’s been a while since Tester has led in a poll, and Sheehy has built up a seemingly ever-increasing lead. Yet, as the recent debate between the candidates demonstrated, Tester isn’t going down without a fight. He hit Sheehy on abortion (“Sheehy has called abortion terrible and murder. That doesn’t sound to me like he’s supporting the woman to make that decision”), on immigration (“Sheehy said he wouldn’t vote for [the immigration bill] even before it was out to be read,” suggesting he was beholden to Donald Trump), and on Native Americans (“You’re a big guy, just apologize” …Sheehy did not apologize).

Seizing on abortion and Native American issues may prove astute, as both are particularly salient in the state. Native Americans make up 9% of the population, and Tester has spent significant time building support with this community, an effort likely to translate into meaningful votes that could help close the gap between him and Sheehy. And Montanans will vote on a ballot measure seeking to protect the right to abortion within the Montana constitution this November (abortion is protected by a ruling of the state’s supreme court already). Though there is good reason to think that abortion ballot measures like this may not necessarily juice Democratic turnout, Montana’s libertarian streak (“I like the right to abortion. I like my guns and want the government out of my business,” noted Lee Banville, the director of the University of Montana’s School of Journalism) may see the proposal over the finish line… if only slightly boosting Tester among some independents, in the process.

Tester also has a substantial fundraising advantage, about 3-to-1 in both raising and spending money in the race. The effect of advertising is likely slim, but as a small, cheap state to advertise in, this gives Tester a leg up in terms of controlling the message and keeping Montanans locked on the issues he wants. Especially as national Democrats need to hedge their bets playing defense and pivot to offense in Florida and Texas, it is reassuring that Tester can keep his own.

But, like Joe Donnelly, Heidi Heitkamp, Doug Jones, and Claire McCaskill before him – all fairly moderate, high quality Democratic incumbents who went down in deeply Republican states over the last six years – deep partisanship is proving to be insurmountable for Tester. Though, unlike many of them, Tester held on once already thanks to his deep ties and independent streak in his small state, this relationship has frayed as Montana has enjoyed steady growth since 2018, gaining about 70,000 people. Many of these newcomers – like Sheehy (who moved to the state in 2014) – are wealthy conservatives, something that Tester has attempted to seize on given increased housing unaffordability; of course, it could also backfire against the incumbent party in power: Democrats (and, by extension, Tester). Even if Tester can stick the landing on that issue, he still faces the problem of potentially thousands of new, high-propensity-to-vote Republicans in Big Sky Country. He may have a reputation among longtime Montanans who are willing to split their vote, and Tester has worked hard for a couple of years to distance himself from national Democrats and Joe Biden, but he’s still a fairly reliable Democrat. New conservative voters, or those riled up by an additional six years of staunch partisanship, may turn against him.

With what should be a sizable incumbency advantage given Montana’s small population and his lengthy relationship with the state, Tester may still defy the odds, and he certainly gives Democrats more of a fighting chance to keep the seat any other candidate would. But, for now, the two races most likely to determine whether Republicans will control the Senate are the United States presidential election and the Senate election in Montana. The pressure’s on.