Illinois held statewide major party primaries on March 17, 2020. All 18 U.S. House districts were on the ballot, along with the Class II U.S. Senate seat currently held by Dick Durbin (D). The general election is scheduled for November 3, 2020.
Eighteen incumbents filed for re-election; Illinois’ 15th Congressional District incumbent John Shimkus (R) was the only federal officeholder in Illinois who did not file for re-election. All but one incumbent on the primary ballot advanced to the general election. 3rd District incumbent Dan Lipinski (D) lost to challenger Marie Newman in the Democratic primary.
Two seats had no candidates on either the Democratic or Republican primary ballot. In the 8th District, no Republicans filed for the ballot, and in the 18th District, no Democrats filed for the ballot. All other seats saw at least one candidate from the Democratic or Republican parties in the primary. Eleven incumbents were unopposed in the primary and advanced automatically to the general. No Republican incumbents faced challengers. In addition to Lipinski, the following incumbents faced primary opposition: Bobby Rush (D-1), Robin Kelly (D-2), Mike Quigley (D-5), Danny K. Davis (D-7), Raja Krishnamoorthi (D-8), and Bill Foster (D-11).
Entering the 2020 election, the U.S. congressional delegation from Illinois has two Democratic U.S. Senators, 13 Democratic U.S. Representatives, and five Republican U.S. Representatives. The U.S. Senate has 45 Democrats, 53 Republicans, and two independents who caucus with the Democratic Party. Only 35 out of 100 Senate seats are up for election. A majority in the chamber requires 51 seats. The U.S. House has 232 Democrats, 197 Republicans, one independent, and five vacancies. All 435 seats are up for election. A majority in the chamber requires 218 seats.