**Idaho's 2026 U.S. Senate contest features incumbent Republican Jim Risch facing independent Todd Achilles in a race rated Solid Republican, with limited national attention or competitive dynamics that typically suppress general-election participation.** Roughly 969,000 registered voters participate in a state where Republicans hold a strong majority and recent primaries showed only about 30% turnout. Historical midterm patterns, including 595,000 votes in 2022, point to moderate participation around 600,000–680,000 ballots, consistent with the market's leading ranges. The Democratic nominee's withdrawal earlier this cycle further reduces cross-party mobilization, while in-migration and localized legislative interest provide only modest counter-pressure. Traders price these ranges highest because the contest lacks the turnout drivers seen in presidential or closely fought years.