Two Republican incumbents lost in the Montana Senate primaries on June 2. This was the first year since 2010 in which more than one incumbent lost in the chamber's primaries.
At the start of Montana's 2025 state legislative session, nine Republican senators voted with the chamber's Democrats to change procedural rules for the session. In May 2025, KTVH's Jonathon Ambarian wrote, "It was only the start of what became a session-long storyline, as that group of nine went on to vote against GOP leadership on numerous procedural motions and some key legislation." The Montana Republican Party censured the nine senators in April 2025.
The Daily Montanan's Micah Drew wrote after the March 2026 filing deadline for this year's legislative elections, "The well-documented rift in the Republican party between moderate members, including the infamous 'Nasty Nine' senators who worked with a bipartisan coalition in 2025, will be on display this spring as more conservative candidates seek to oust moderates."
