Idaho’s solidly Republican Senate contest between incumbent Jim Risch and independent challenger Todd Achilles features limited overall competitiveness, which tempers broad voter mobilization compared with battleground states. Roughly 1 million registered voters and steady population growth set a baseline, while 2024 general-election participation near 63 percent and the May 2026 primary’s elevated 30 percent rate provide recent benchmarks. Early voting and absentee options remain available through November 3, yet the absence of high-profile ballot measures or intense statewide races has kept enthusiasm moderate. Traders therefore cluster probabilities on the 600,000–680,000 vote range, reflecting expectations of typical midterm participation without major late catalysts to push totals substantially higher or lower.