Brown, Manchin and Tester all survived their party’s difficult 2018 cycle after then-President Donald Trump pushed their states further rightward. Before that, they won reelection in 2012 while sharing the ballot with then-President Barack Obama. Now, the trio of Democrats is staring down their toughest political challenge yet: pulling a Susan Collins.

The moderate GOP Mainer successfully persuaded her state’s voters to split their tickets in a presidential year; Collins won reelection by 8 points in 2020 even as Biden defeated Trump by 9 points in her state. For Democrats to hang onto their 51-seat majority, they need Collins-style performances from at least two of their three red-state incumbents in an era of declining split-ticket voters.

While Brown and Tester are all in, Manchin hasn’t decided whether to run again, and Biden hasn’t made it official yet either. That makes Tester’s reelection decision all the more critical to the party — he’s probably the only Montana Democrat with a shot. At the moment, Democrats’ hopes of holding the Senate largely ride on Tester and Brown defying their states’ political leanings.

A decade ago, ticket-splitting was a far more common political phenomenon: Democrats won Senate races everywhere from Missouri to Indiana to North Dakota in 2012, even as Obama lost those states. Sen. Gary Peters (D-Mich.), the party’s campaign chair, acknowledged that in the current environment “it’s a little bit harder to differentiate yourself” but if anyone can do it, it’s his incumbents.

“Just look at how these folks got elected. Jon Tester ran well above the presidential race. Manchin has done that,” Peters said in an interview. “The candidates who are running have already demonstrated that they have a unique plan, a very individualized brand. And that brand will prevail in the end.”

Peters’ GOP counterpart on 2024 campaigns, Montana Sen. Steve Daines, predicted voters would see something simpler from red-state Democrats running alongside Biden: “They run scared. And they run away.” In 2020, Daines trounced a strong Democratic nominee, Steve Bullock, even as the former governor significantly overperformed Biden in Montana.

Among the three red-state Democrats, Manchin is most akin to Collins in terms of keeping their distance from their parties’ presidential nominees. Manchin didn’t support Obama in 2012, nearly pulled his backing from Hillary Clinton in 2016, and though he supported Biden in 2020 he seems unlikely to be vocal either way in 2024.

“In West Virginia, you know, it doesn’t make a difference,” Manchin said. “Joe Biden’s going to get beat so bad no matter what in my state. It’s just me. I’m not going to be campaigning for or against anybody else.”

Divided government will test Manchin’s sway. He’s championing an energy permitting overhaul that fell short last year and pushing the Biden administration on rolling out the energy, tax and health care bill he helped write last year. But each of the party’s three red-state senators has a prominent perch to generate more accomplishments before they’d face voters: Brown chairs the Banking Committee, Manchin chairs the Energy Committee and Tester chairs the Veterans Affairs Committee.

Meanwhile, Republicans will look to limit the three senators’ successes and drive a wedge between Biden and Senate Democrats. The chamber’s Republicans are plotting disapproval votes on federal regulations regarding sustainable investments, trucking emissions, water regulations and Pentagon environmental performance.

Biden will certainly veto those GOP efforts if they prevail, but their political intention is clear: Squeeze Democrats. Simultaneously, those votes offer an opportunity for Senate Democrats to separate themselves from the president.

“There are obviously [Democratic incumbents] who are paying attention to politics back home,” said Minority Whip John Thune (R-S.D.).

As challenging as 2024’s map is for Senate Democrats, it’s not as rough as 2018, when they had to defend 10 seats Trump had just won. Biden’s presidential win shored up Democrats’ brand in Pennsylvania, Wisconsin and Michigan, and if they can win those states at the presidential level again, it’s good news for their Senate hopefuls.

That puts a more intense focus on Ohio, West Virginia and Montana as the states that will decide the majority. And Republicans are looking at the basic math: In 2020, Trump won West Virginia by 39 points, Montana by 16 points and Ohio by 8 points.

The rest of next year’s battleground Senate races are in states Biden won, albeit in some cases quite narrowly: Wisconsin, Michigan, Nevada, Pennsylvania and Arizona. Democrats in those states are far more likely to run with Biden than as a check on him — though the Copper State could see a three-way race if independent Sen. Kyrsten Sinema seeks a second term.

Summing up her reelection theme in an interview, Sen. Tammy Baldwin (D-Wis.) cited Biden’s recent State of the Union: “Between the House, the Senate and this president, there has been exceptional accomplishment. But we haven’t finished the job.”

Even in Ohio, Brown said he’d “assume” he’ll campaign with Biden even if the president is unlikely to consider his state a must-win.

“I run my own race, and my own brand. So, I’m not going to run from Biden,” Brown said. “He’s also delivered more than any president in recent history.”

Even Manchin sounds much like Brown or Baldwin when discussing what Democrats accomplished during the previous Congress. But because Biden is unpopular in West Virginia, it’s up to him to convince voters what they got out of it.

“There’s more coming for the state of West Virginia because of what we’ve done. Now, they’re not going to give that credit to a Democratic president,” Manchin said.

Manchin endorsed Collins in 2020, when the Mainer did not support Trump and largely ran on her lengthy record. Her reelection race initially flared with liberal outrage over her vote for Supreme Court Justice Brett Kavanaugh and culminated in one of the most expensive Senate races in the country.

Through it all, Collins trailed in the polls as then-Minority Leader Chuck Schumer mounted an aggressive bid to flip her seat. Yet in the end, Democrats fell short trying to nationalize the race in a state with few transient voters.

Offering some advice from that experience to Manchin, Brown and Tester — all of them similarly well-known back home, just like her — Collins put it this way: “People know me personally. And when Chuck Schumer was running vicious ads, people just didn’t believe it.”