So far this year, 156 state legislative incumbents—39 Democrats and 117 Republicans—have lost to primary challengers.

Across the 33 states that have held primaries, 4.7% of incumbents running for re-election have lost, an elevated level of incumbent losses compared to previous cycles.

These totals include data from Arizona, Kansas, Michigan, Missouri, Ohio, and Washington, which held state legislative primaries on Aug. 2. No incumbents have lost, so far, in Arizona, Michigan, and Washington, though races featuring incumbents remain uncalled. For the remaining states:

• Kansas: one Democrat and three Republicans lost;
• Ohio: one Democrat and two Republicans lost; and,
• Missouri: four Democrats and two Republicans lost.

This year, Republican incumbents have lost at a higher rate than Democrats. Of the 1,901 Republican incumbents who filed for re-election, 117 (6.2%) have lost to primary challengers. For Democrats, 39 of the 1,432 who filed for re-election (2.7%) have lost.

Thirty-four of these 156 incumbent defeats (22%) were guaranteed due to redistricting. When states redraw legislative lines, incumbents can oftentimes end up in a new district with other incumbents leading to incumbent v. incumbent primaries or general elections. Since, in these races, there are more incumbents running than nominations or seats available, at least one incumbent must lose.

Of the 33 states that have held primaries so far, nine have Democratic trifectas, 18 have Republican trifectas, and six have divided governments. Across these 33 states, there are 4,306 seats up for election, 70% of the nationwide total.

The figures for 2022 will likely increase. There are currently 87 uncalled primaries featuring incumbents: 24 Democratic, 33 Republican, and 30 top-two.

You can view more information about state-specific and historic information regarding incumbent defeats by clicking “Learn More” below.