Mike Simpson's long incumbency since 1999 and the strongly Republican lean of Idaho's 2nd Congressional District underpin trader consensus around his 94.9% implied probability. The seat covers eastern Idaho and parts of the Boise area, where Republican candidates have consistently prevailed in recent cycles. Simpson recently secured his party's nomination after fending off primary challengers, while Democratic nominee Ellie Gilbreath has received limited statewide visibility or funding. Historical voting patterns and low turnover in similar districts reinforce this positioning. Late developments such as a significant scandal, health event affecting the incumbent, or an unusually strong national Democratic wave could narrow the gap before the November 2026 general election.