Trump, Rosendale, Sinema: The big decisions shaping the Senate GOP's odds

Senate Republicans have a solid shot in the battle for Senate control this year after landing some of their top recruits and nabbing an almost certain pickup. Still, several critical factors could hurt their bid to take back power.

The biggest drama is out West, where independent Arizona Sen. Kyrsten Sinema and Republican Montana Rep. Matt Rosendale are mulling their futures. Their decisions will have crucial implications across the entire map, where Republicans either need to net two seats or win the presidency and gain just one.

Sen. Joe Manchin’s (D-W.Va.) retirement has GOP senators confident they’ve got one seat locked down. Winning another could depend heavily on Sinema, Rosendale and a slew of other unknowns.

If Sinema runs for a second term, she would create an unpredictable three-way race as an underdog independent attempting to peel voters from Rep. Ruben Gallego (D-Ariz.) and Republican Kari Lake, her party's presumptive nominee. Rosendale, meanwhile, would create a massive headache for Republicans if he follows through on months of build-up and challenges Tim Sheehy for the GOP nomination in Montana, which is one of the party’s top two Senate targets.

There's more in flux: Republicans are closely watching whether former President Donald Trump will weigh in on crucial contested primaries in several purple states. And there are still big questions about whether last-minute recruits will help expand the map beyond Ohio, Montana and a half-dozen battlegrounds. Oh, yeah, and the most well-known liberal senator in the country might retire — or serve deep into his 80s.

Here’s what POLITICO is watching as the battle for the Senate heads into a defining stretch:

Big Sky Republican divides

Rosendale’s decision is probably the most important to the Senate map. It would create a GOP primary that could force the national party to spend tens of millions of dollars and divide a state party that needs to throw a perfect game to beat incumbent Sen. Jon Tester (D-Mont.).

Tester beat Rosendale in 2018 despite support from Trump and Republicans of all stripes. Since then, Rosendale won a House seat and developed a reputation as a notorious rabble-rouser, helping oust former Speaker Kevin McCarthy and now advocating hardline shutdown positions to get tough new border policies.

He’s signaled to Republicans for months he plans to run. And the party has made it absolutely clear they don’t want him in the Senate race.

“I hope he stays in the House and continues to develop seniority there,” said Sen. Steve Daines (R-Mont.), who runs the Senate GOP’s campaign arm.

That hasn't dissuaded Rosendale. He has needled Sheehy by yoking him to Senate Minority Leader Mitch McConnell and suggested to colleagues that he’s going to get in the race. He’s continuing to campaign outside his district and is set to host campaign events with Rep. Matt Gaetz (R-Fla.).

“Steve Daines has made it exceedingly clear that the Senate committee is supporting Tim Sheehy,” Rosendale said in a brief interview. “People across Montana still overwhelmingly would rather have someone who is an independent voice for them and not answering to Mitch McConnell.”

The filing deadline is March 11. Tester's not making any bets, saying in a brief interview: “I can’t predict what the hell he’s going to do."

Sinema's choice

The Arizona senator ditched the Democratic Party more than a year ago and only solidified her independent status since then, pursuing a border and immigration agreement that could augment her legacy of bipartisan deal-cutting. Before that, she helped broker a gun safety deal, rejected changes to the filibuster and cut down some provisions in the Inflation Reduction Act.

And in her typical reserved style, well, she's still not looking to talk about her reelection decision-making.

“I’m not thinking about that at all right now. You know what I am thinking [about]?” Sinema said in a brief interview. “The border."

Sinema, who generally aligns with Democrats on key votes, has until April 8 to decide to run again — but in reality, she would need to start collecting signatures to make the ballot well before then. As an independent candidate, she will face more onerous signature requirements. And if she decides to run, the race would be challenging, to say the least. She consistently lags behind both Gallego and Lake in polls, though she has more than $10 million in her campaign coffers.

“There’s not a path that we can see for Kyrsten in that race,” Daines said. “It’s going to be Kyrsten’s decision, but I think it’s going to be a difficult path for her.”

Still, a Sinema reelection bid would create a chaotic and indecipherable race in a challenging state. It would undoubtedly affect the campaign strategies of both of her foes, even if she starts out in third place.

The Trump effect

Trump handpicked several of the Senate GOP’s candidates in 2022. It didn't go well — Republicans blew winnable races in states like Arizona and Pennsylvania — but they swear it’ll be different this time.

Trump has backed several of the GOP’s preferred candidates this cycle and, as of now, Trump and Daines differ on only one race: Ohio, where the National Republican Senatorial Committee is neutral, and Trump has endorsed businessperson Bernie Moreno. Yet there’s plenty of opportunities for more mischief.

An endorsement from the former president could whittle down an unruly field in Michigan, where a slew of Senate contenders are vying for his support: Former Reps. Mike Rogers and Peter Meijer, former Detroit Police Chief James Craig and businessperson Sandy Pensler. And former Rep. Justin Amash, who became a libertarian after voting to impeach Trump, is mulling a run — as a Republican.

The jockeying for Trump’s favor has only grown more heated as he surges in the presidential primary. Pensler just released an ad cataloguing Rogers’ past anti-Trump comments.

“They know he's going to be the candidate,” Rep. Jack Bergman (R-Mich.) said of Trump. The candidates "all want" his endorsement, he added, but "the question is: What's the advantage to him to give it?"

There’s also a crowded primary in Nevada where Trump could weigh in, featuring his former ambassador to Iceland Jeffrey Gunter, hardline conservative Jim Marchant and NRSC-backed veteran Sam Brown. Plus there's Montana, where Trump's endorsement could become a key factor if Rosendale gets in — particularly after the lawmaker infamously snubbed Trump on the House floor.

The final recruits

Wisconsin is the preeminent battleground of modern day politics. So how the heck does Sen. Tammy Baldwin (D-Wis.) not have a real GOP challenger yet?

The two-term senator’s expecting one soon: Eric Hovde, a wealthy businessperson who ran for Senate in 2012. Hovde has been interviewing potential staff and consultants ahead of his likely run, according to a person familiar with his plans who was granted anonymity to speak candidly.

“Steve Daines … indicated [Hovde] was jumping and had their full support. So that’s what we’re planning” for, Baldwin said in an interview. Still, she said “there may well be” a more crowded primary.

Hovde’s launch would give the Senate GOP its final recruit in their critical battleground targets. But other strong candidates could bring reach seats into play. On the Democratic side, there’s hope Rep. Colin Allred (D-Texas) and former Rep. Debbie Mucarsel-Powell (D-Fla.) can catch fire against conservative Sens. Ted Cruz (R-Texas) and Rick Scott (R-Fla.).

Nella Domenici, the daughter of New Mexico’s last GOP senator, just launched a run in her typically blue state. And Republicans are always dreaming of big names like Glenn Youngkin in Virginia, though Daines said he hasn’t talked to the Virginia governor about it.

A progressive icon's big decision

Vermont is no battleground, but it is the home of the highest-profile liberal senator in Congress: Bernie Sanders.

The two-time presidential candidate teased this month that he will make an announcement in the “near future” about his plans. Sanders will be 83 on Election Day, but it would be wrong to assume he’s retiring because of his age — he's only gained political power since his torrid presidential campaigns in 2016 and 2020, becoming Health, Education, Labor and Pensions chair.

“I hope he runs. He's special. He's played a special role in the country and a special role in American politics and certainly in Vermont,” said Sen. Peter Welch (D-Vt.).

If Sanders were to retire, it would leave a void in the progressive movement's leadership. The gruff liberal is more willing than most in the Senate Democratic caucus to challenge President Joe Biden or other party leaders over hot-button topics, ranging from arming Israel to endorsing primary challenges against his colleagues.

That propensity has seemingly endeared him to voters; Welch called him the “the most popular politician in the country.”