Delaware’s at-large congressional district has favored Democratic candidates for decades, reflecting consistent statewide voting patterns and the party’s structural advantages in voter registration and turnout. Incumbent Sarah McBride, elected in 2024 by a 16-point margin after succeeding Lisa Blunt Rochester, faces no serious primary opposition ahead of the September 15 contests and enters the November general as the clear frontrunner. Republican primary candidates remain low-profile with limited fundraising visibility or statewide name recognition. Traders assign the Democratic Party a 93.5 percent implied probability because historical base rates, the absence of competitive polling shifts, and the district’s recent election results reinforce expectations of continuity. A Republican victory would require an unusually large national wave, a major unforeseen development involving the incumbent, or a dramatic primary upset that produces an unusually strong challenger.