Rep. Matt Rosendale is running for Senate again in Montana, kickstarting a messy fight for the Republican nomination that many party leaders had hoped to avoid in a state that could tip the partisan balance of power in the chamber.
Rosendale, who failed to unseat Sen. Jon Tester in 2018, officially launched his bid for a rematch with the three-term Democrat on Friday.
"We’ve made great accomplishments in the House, only to see them die at the hands of Mitch McConnell and Chuck Schumer in the Senate," Rosendale said in a post on X after filing for the race. "Montanans want a Senator that fights for WE, THE PEOPLE, not the D.C. Cartel!"
Rosendale's entry pits him first against former Navy SEAL Tim Sheehy, a political newcomer who for months has enjoyed backing from the National Republican Senatorial Committee and other key establishment figures. Hours after Rosendale announced his candidacy, former President Donald Trump endorsed Sheehy.
"I also respect Matt Rosendale, and was very happy to Endorse him in the past — and will Endorse him again in the future should he decide to change course and run for his Congressional Seat," Trump wrote in a post on Truth Social. "But in this instance, Tim is the candidate who is currently best-positioned to DEFEAT Lazy Jon Tester, and Regain the Republican Majority in the United States Senate."
Trump's aides had been frustrated by what they view as Rosendale’s lack of loyalty, NBC News reported this week.
The primary is set for June 4.
NRSC Chairman Steve Daines, who also represents Montana in the U.S. Senate, issued a statement criticizing Rosendale's decision "to abandon his seat and create a divisive primary."
"Whichever party wins the Montana Senate seat will control the United States Senate in 2024, and Republicans cannot risk nominating a candidate who gave Jon Tester the biggest victory of his career," Daines added.
Alluding to the intraparty hostility, Montana Democratic Party spokesperson Hannah Rehm proclaimed that "the NRSC’s greatest nightmare in Montana came true."
Montana is a top GOP target this year as one of three states — along with Ohio and West Virginia — represented by Democratic senators that Trump carried in 2020. Sen. Sherrod Brown's re-election campaign in Ohio is expected to rival Tester's in Montana for national money and importance, while Sen. Joe Manchin's retirement in West Virginia is likely to make that state far easier for Republicans to flip.
Tester has proven to be a formidable opponent since he was first elected in 2006, stressing his deep roots in Montana, including his experience as a farmer and his bipartisan work on issues such as veterans' health care.
In 2012, even as then-President Barack Obama lost Montana by 14 percentage points, Tester won a second term by 4 points, earning 35,000 more votes than the president. Tester defeated Rosendale by nearly 4 points in 2018.
In anticipation of another hotly contested race, Tester has been building up his campaign coffers, ending 2023 with $11.2 million on hand. And his campaign has already been active on the airwaves, spending $5.7 million on ads so far, according to the ad tracking firm AdImpact.
Tester and his allies have dominated the Montana airwaves so far, with the Democratic group Last Best Place PAC spending $6.6 million, largely targeting Sheehy. The group is tied to Senate Majority PAC, the main Democratic super PAC focused on Senate races.
Sheehy, meanwhile, has spent $3.4 million on ads, launching spots touting his background as a former Navy SEAL and businessman. He ended 2023 with about $1.3 million on hand — less than the roughly $1.7 million Rosendale reported in his House campaign fund, which can be tapped for a Senate bid.
Rosendale's fundraising activity over the last quarter, however, was far less robust than Sheehy's — the congressman reported raising $97,000 to Sheehy's $1.6 million. The disparity raised questions about how seriously Rosendale was taking the prospects of both an expensive primary clash and a potential general election.
Other external dynamics have shaped the race in recent months. Aside from the NRSC, Sheehy also has endorsements from Montana Gov. Greg Gianforte and the state's other congressman, Rep. Ryan Zinke.
The Trump factor could loom large. Rosendale aligned with Trump in rejecting, without credible evidence to the contrary, the results of the 2020 presidential election. But he split with the former president last year when Trump backed Kevin McCarthy for House speaker. Rosendale's refusal to accept a phone call from the former president during the leadership fight was documented by photographers and became a point of tension in Trump world.
A pivotal moment of friction came in December at Trump’s Mar-a-Lago resort in Florida, where Rosendale, who was there for a fundraiser, approached the former president as he passed through a lobby in golf attire for an impromptu photo that the congressman shared on social media. Trump advisers considered it an ambush, according to four sources familiar with the encounter. And they were particularly incensed about what they saw as Rosendale’s attempt to project a close relationship, even though he had not yet endorsed Trump's 2024 presidential campaign. (Rosendale has since endorsed Trump.)
A source close to Rosendale maintained this week that the Mar-a-Lago meeting with Trump was cordial and a coincidence.
"When others hesitated and showed disloyalty, Tim Sheehy proudly endorsed President Donald J. Trump early on and was honored to speak in support of him during his historic Iowa Caucus victory," the Sheehy campaign said in a statement responding to Rosendale's announcement Friday. "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."
Rosendale could benefit from support from Trump allies who are unhappy with the NRSC's involvement and eager to tie Sheehy to Senate GOP Leader Mitch McConnell, who is viewed as an enemy of Trump's MAGA movement. Rep. Matt Gaetz, R-Fla., toured Montana with Rosendale last month. Former Trump adviser Steve Bannon has railed against Sheehy's establishment pedigree on his daily podcast, which is influential with right-wing voters.
In a post this week on X, Rep. Anna Paulina Luna, R-Fla., wrote that Rosendale would have her endorsement for Senate.
"I’m tired of hacks running and winning only to take orders from McConnell," Luna wrote. "He’s part of the problem."