Representative Ashley Hinson is widely expected to prevail over Jim Carlin, a far-right former state senator who lost a 2022 primary challenge to Senator Charles E. Grassley.

The expected vote is the total number of votes that are expected in a given race once all votes are counted.

At the Union Club in Missoula, Mont., the crowd gathered for Sam Forstag, the former smoke jumper backed by Senator Bernie Sanders, is festive and dancing to live rock music.