By Geoff Pallay

MADISON, Wisconsin: Kansas voters sent an overwhelming message to incumbents last night, knocking off 18 current sitting members of the state legislature in primaries. To put that figure in context, in 2010, the most incumbents defeated in a state legislative primary was in Rhode Island, where 10 incumbents lost to challengers. The 18 incumbents defeated is by far the most of any state so far during the 2012 legislative season.

On July 26, 2012, Ballotpedia released an analysis of the rate at which incumbents are being defeated by challengers in state legislative primaries. That study was conducted roughly halfway through the primary season, and found that 76 incumbents had been defeated through the first 48 percent of primaries. After each primary, we will update those figures. This update focuses on Kansas, Michigan, Missouri and Washington. A total of 31 incumbents fell to opponents on August 7, 2012. That brings the total incumbents defeated in 2012 legislative primaries to 134.

Of the 134 incumbents that have lost a primary in 2012, 44 are Democratic incumbents and 90 are Republican incumbents.

Kansas

A total of 129 Kansas legislative incumbents filed for re-election. Fifty-three incumbents faced a primary, and opponents were victorious in 18 of those races. Thus, 33.96 percent of opposed incumbents were defeated by their primary challenger.

There are still four races involving an incumbent that are too close to call. Thus, the total number of incumbents defeated in Kansas could still increase.

The 18 total incumbents who lost last night is significantly higher than the five total incumbents defeated in a 2010 primary in Kansas.

Michigan

A total of 91 Michigan legislative incumbents filed for re-election. Thirty-six incumbents faced a primary, and opponents were victorious in five of those races. Thus, 13.89 percent of opposed incumbents were defeated by their primary challenger.

The five total incumbents who lost last night is significantly higher than the one total incumbent defeated in a 2010 primary in Michigan.

Missouri

A total of 126 Missouri legislative incumbents filed for re-election. Thirty-five incumbents faced a primary, and opponents were victorious in eight of those races. Thus, 22.86 percent of opposed incumbents were defeated by their primary challenger.

The eight total incumbents who lost last night is significantly higher than the three total incumbents who lost a 2010 primary in Missouri.

Washington

A total of 93 Washington legislative incumbents filed for re-election. Only 14 incumbents faced a primary. Because of Washington’s voting by mail system, not all results are yet available. However, the early indications of results are that no incumbents are expected to lose in the primary. Washington uses a blanket primary system — meaning the top two candidates, regardless of party, advance to the general election.

In 2010, one Washington incumbent was defeated in a legislative primary.

What’s next

The next state legislative primary takes place Saturday in Hawaii. Then, there will be four primaries next Tuesday, August 14 in the following states: Connecticut, Florida, Minnesota and Wisconsin.

Cumulative table of results

Full study

• Primary Change: Anti-Incumbency Voting Patterns in State Legislative Primaries