On August 4, Arizona, Kansas, Michigan, Missouri, and Washington held statewide primaries. A total of 48 congressional seats—45 U.S. House seats and 3 U.S. Senate seats—were on the ballot. In the races for those 48 seats, 41 incumbents advanced to the general election, two incumbents lost to challengers, and five incumbents did not run for re-election.
Appointed incumbent Martha McSally (R) won the Republican primary in the special election for former U.S. Senator John McCain’s seat. She will face Democrat Mark Kelly in the November general election. Write-in votes, including those in the Libertarian primary for U.S. Senate, have not been counted as of the time of publication. In the races for Arizona’s nine U.S. House seats, all nine incumbents—five Democrats and four Republicans—were successful in their primary bids and advanced to face challengers on November 3.
Sen. Pat Roberts (R) did not file for re-election, leaving his Class II Senate seat open. Democrat Barbara Bollier won the Democratic primary for the seat, while current congressional Rep. Roger Marshall defeated a field of 11 Republican candidates to advance to the general election. In Kansas’ four U.S. House districts, two of the three incumbents who filed for re-election—District 3 Rep. Sharice Davids (D) and District 4 Rep. Ron Estes—advanced unopposed from their primaries. District 2 incumbent Rep. Steve Watkins lost the Republican primary to challenger Jacob LaTurner. Rep. Marshall’s District 1 House seat was open due to his run for Senate.
In the race for Michigan’s Class II Senate seat, incumbent Sen. Gary Peters (D) ran unopposed in the Democratic primary. He will face Republican John James—who also advanced unopposed from the Republican primary—in the November general election. In the races for Michigan’s 14 U.S. House seats, all 12 incumbents who filed for re-election won their primaries. Two incumbents—District 10 Rep. Paul Mitchell (R) and District 3 Rep. Justin Amash (L)—did not run for re-election.
Missouri does not have a U.S. Senate seat up for election in 2020. All eight of Missouri’s U.S. House seats are up for election, and all eight incumbents filed for re-election. Of those, seven advanced from their primaries. District 1 Rep. William Lacy Clay lost the Democratic primary to challenger Cori Bush.
Washington holds top-two primaries in which all candidates are listed on the same primary ballot and the top two vote-getters advance to the general election, regardless of party affiliation. No Senate seat is up for election in Washington in 2020. In Washington’s 10 U.S. House district races, nine incumbents ran for re-election and all advanced to the general election. District 10 Rep. Denny Heck (D) is running for Washington lieutenant governor, leaving his seat open. In the District 2, 7, 8, 9, and 10 races, the second-place finisher who will advance to the November general election remains uncalled as of publication.
These primaries were the 32nd through the 36th to take place in the 2020 election cycle. The 37th primary was held on August 6 in Tennessee.