Trader consensus centers on 600K-680K total ballots in Idaho’s U.S. Senate contest, reflecting registered-voter totals above one million, steady population growth, and midterm turnout patterns historically near 42-45 percent of registered voters. The 2022 Senate race produced roughly 580K votes; updated registration and modest primary participation near 30 percent in May 2026 support incremental increases into the leading buckets. An independent challenge from Todd Achilles has introduced additional campaign activity and polling interest compared with prior cycles, yet the race remains rated Safe Republican by multiple forecasters, limiting any sharp turnout surge. Absent major late developments or unusually high early-voting volume, these ranges align with the most probable absolute participation levels.