Democrat Jon Tester just got some added competition in his bid for a fourth term in the U.S. Senate. Republican Matt Rosendale, who represents Montana's Second Congressional District, announced on Friday that he plans to run for the Senate in 2024. Should he win the nomination, he'd face a rematch against Tester, who bested him by 3.5 points in 2018. 

Since then, Rosendale successfully ran for the at-large U.S. House seat vacated by Greg Gianforte (R), who opted to run for governor in 2020. In that race, Rosendale was endorsed by former President Donald Trump and won a six-way Republican primary before facing and defeating Democrat Kathleen Williams. 

After the 2020 census, Montana regained a second congressional district, and Rosendale ran for that seat in 2022, again receiving a Trump endorsement. After securing the Republican nomination, Rosendale notched a decisive victory over the Independent and Democrat candidates, with 56.6 percent of the vote. 

But before he can look to that rematch against Tester, Rosendale, 63, will need to win the Republican primary, which means he'll have to defeat Navy SEAL Tim Sheehy, 38. 

Rosendale announced his candidacy on X Friday morning. 

🚨This morning, I officially filed for the U.S. Senate.

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.

Montanans want a Senator that fights for WE,THE PEOPLE, not the D.C. Cartel! pic.twitter.com/8ZkeCttCFj

— Matt Rosendale (@MattForMontana) February 9, 2024

This morning, I officially filed for the U.S. Senate.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.Montanans want a Senator that fights for WE,THE PEOPLE, not the D.C. Cartel!

Following the announcement, Sheehy, who's already been endorsed by Gianforte, Sen. Steve Daines (R-MT) and Rep. Ryan Zinke (R-MT), responded with a pointed barb. 

Matt, this is your 8th political run in the last 14 years and you still can't say Montana right. It's going to be a long 4 months…. pic.twitter.com/GzY2iJ4vXM

— Tim Sheehy (@SheehyforMT) February 9, 2024

Matt, this is your 8th political run in the last 14 years and you still can't say Montana right. It's going to be a long 4 months….

Rosendale was one of eight Republicans who voted to oust former House Speaker Kevin McCarthy in October of last year. 

It looks as though this time around, however, Rosendale won't have the coveted Trump endorsement in the primary. That's going to Sheehy, as the former president announced on Truth Social Friday afternoon: 

I LOVE MONTANA! Tim Sheehy is an American Hero and highly successful Businessman from the Great State of Montana. He is strongly supported by our incredible Chairman of the NRSC, Steve Daines, and many other patriotic Senators and Republicans who have endorsed our Campaign to, MAKE AMERICA GREAT AGAIN! 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. 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. Tim is a Political Outsider, Strong on the Border, the Military/Vets, and our constantly under siege Second Amendment. He will stand tall in the fight against the Radical Left Democrats, who are Destroying our Country. Also, he is far more likely to Defeat Lazy Jon. America First Patriot Tim Sheehy has my Complete and Total Endorsement!

Montana's primary is set for June 4, 2024.