The entry of Rep. Matt Rosendale (R-Mont.) into Montana’s Senate race is threatening the party with a bitter and bruising primary ahead of a general election seen as central to its effort to regain control of the upper chamber in November.
Rosendale, a member of the conservative House Freedom Caucus, officially filed to enter the GOP race Friday, jumping in alongside businessman Tim Sheehy, who is seen by many members of party leadership as the stronger candidate. Both men are looking to take on Sen. Jon Tester (Mont.), one of the most vulnerable Democratic incumbents up for reelection this year.
In a sign of how concerned Republicans are about Rosendale, the party quickly moved to coalesce around Sheehy on Friday. Former President Trump, who until this point had stayed out of the primary, formally endorsed Sheehy, prodding Rosendale to instead run for his House seat. South Dakota Gov. Kristi Noem (R), a potential vice presidential pick, also came out in support of Sheehy, while Sen. Steve Daines (R-Mont.), the head of the National Republican Senatorial Committee (NRSC), blasted Rosendale in a statement.
But Rosendale has dug in his heels, saying in a post on X, formerly known as Twitter, that he plans to stay the course.
“I love President Trump,” Rosendale wrote. “But he needs actual fighters in the U.S. Senate to enact his Agenda 47 – and that’s me and not Mitch McConnell’s hand pick, Tim Sheehy. I’m going to win this primary, defeat Jon Tester in November and together we will Make America Great Again!”
The former president’s endorsement came a day after Speaker Mike Johnson (R) faced blowback from his party after reports that he planned to endorse Rosendale, spurring the Speaker to quickly reverse course.
Taken all together, the development suggests Montana is set for “one of the most bitter primary battles” it has seen in recent years, said Paul Pope, a political science professor at Montana State University.
“This is a completely fascinating situation where Republicans appear to be giving themselves an uphill battle to maintain their position in the House and take back the Senate,” Pope said of Rosendale’s entry. “They’re actually making it much, much harsher on themselves.”
Former Navy SEAL Sheehy jumped into the Senate race last summer as the top GOP recruit to take on Tester, a three-term incumbent who is seen as one of the most prominent and vulnerable Democratic moderates up for reelection in 2024.
Though he was a political unknown in the state, Sheehy scored the backing of the NRSC, with Daines reaffirming in his Friday statement that Sheehy has his “full support.”
Rosendale, on the other hand, lost to Tester when he ran for Senate in 2018 before going on to win his House seat in 2020, after campaigning as a Trump ally.
Rumors of another Rosendale bid have been circulating for months, but top Republicans were looking to avoid a Rosendale-Tester rematch as they ready for what Daines recently called “the best map in a decade” for the party to win the Senate majority in 2024.
The Senate race is one of three listed by the Cook Political Report as a “toss-up,” along with Arizona and Ohio.
“Without a doubt, Republicans would much rather not have this primary battle in what was expected to be a close race that could decide control of the U.S. Senate,” said GOP strategist Mike Dennehy, adding that Rosendale’s entry will have a “dramatic impact.”
“I’m sure Republican leaders are tremendously disappointed and upset, and I see no way around a bitter, bitter primary race,” Dennehy said.
Rosendale’s entry is underscoring the opposing factions within the GOP as more traditional conservatives and members of the extreme right find themselves “at war with each other,” Pope said.
The Democrats’ Senate campaign arm said Friday that the Montana GOP primary is “shaping up to be a ‘bloodbath.’”
“It’s a strong matchup,” said Montana State University political scientist Jessi Bennion. “Sheehy is the establishment choice, obviously. The NRSC, Daines, they kind of appointed him as their candidate of choice. But then here comes Rosendale, and Rosendale has a ton of support with the Montana Republican base, with the central committees.”
In Congress, Rosendale voted to overturn the 2020 presidential election results and held out support for Rep. Kevin McCarthy (R-Calif.) in all 14 rounds of voting for the Speakership last year. He later became one of eight Republicans who voted to oust McCarthy from the Speakership back in October.
Johnson’s about-face on an endorsement was the clearest indication of how divisive Rosendale is as a candidate.
“The only thing worse than not getting the Speaker’s endorsement is getting it and then having it taken away,” said Montana-based Republican strategist Erik Iverson, calling the reported switch up “embarrassing.”
Rosendale responded to the news by saying he and Johnson “have always had a great relationship.”
The Montana Democratic Party said the NRSC’s “greatest nightmare in Montana came true” with Rosendale’s bid.
“It totally muddies the water for the NRSC, because now he’s going to be a thorn in their side,” Bennion said of Rosendale.
Iverson, a former chair of the Montana Republican Party, said he doesn’t expect Rosendale’s entry to impact the ultimate November result, though it could still force Sheehy and his supporters to use up money and resources in the primary they’d prefer to save for the general.
“Does it make things more expensive, and all that? Sure. But sometimes the primary election can be good for energizing your donors and your volunteers,” Iverson said.
Dennehy, on the other hand, thinks Rosendale’s entry “automatically” positions him to take the front-runner slot from Sheehy, given his support within the state.
“It will set up the kind of classic Trump vs. establishment primary race that we have seen many, many times before,” Dennehy said.
A spokesperson for Sheehy’s campaign played up his ties to Trump in response to the Rosendale news.
“Both successful businessmen and political outsiders, President Trump and Tim Sheehy cannot be bought and are the conservative warriors we need to put the people of Montana first, drain the swamp, and save our country from the mess Joe Biden and Jon Tester created,” reads the statement.
Trump won Montana by more than 16 points in 2020, and Tester is the last statewide-elected Montana Democrat.
“Montana is critical in the Senate. I mean, this is a genuine pick-up opportunity for the Republicans,” Klink said.
“A strong Republican turnout in 2024 could do [Tester] in in Montana, and could yield a pickup for Republicans, and likely the Senate majority along with it.”