Matt Rosendale seeks rematch against Jon Tester.

Conservative Montana Rep. Matt Rosendale plans to run for the nomination to take on Sen. Jon Tester (D-Mont.) next year, according to sources. Rosendale lost to Tester in 2018 and would almost certainly join the party’s right flank if he can topple the incumbent. His timeline is unclear, but any campaign launch could set him on a collision course with Senate GOP leaders who are working to recruit a fresh face for the must-win contest.