Incumbent Democratic Sen. Dick Durbin, first elected in 1996, declined to seek a sixth term in 2026. This marks the first open Senate race in Illinois since 2010 and the first for this Class II seat since Durbin’s initial election. The Democratic primary has emerged as a three-way contest among Lieutenant Governor Juliana Stratton, Congresswoman Robin Kelly, and Congressman Raja Krishnamoorthi, who has led in polling and fundraising. Governor JB Pritzker and his allies have backed Stratton, while Kelly has drawn support from the Congressional Black Caucus. Former Illinois Republican Party chair Don Tracy is the leading GOP contender, though the Democratic nominee will be heavily favored in the general election given the state’s partisan lean.

In the 2024 presidential election, Kamala Harris carried Illinois by just under 11 points—six points lower than Biden’s 2020 margin—reflecting reduced Democratic turnout in Cook County but not altering the state’s solidly blue status. Democrats hold 14 of 17 U.S. House seats, control both chambers of the state legislature with large majorities, and occupy most major statewide executive offices.