Republican Robin Vos, Wisconsin’s longest-serving Assembly speaker, has presided over efforts to restrict abortions, weaken unions, expand gun rights, and oppose COVID-19 mandates. Despite this, he faces a primary challenger who claims he is too conservative.

The challenger’s argument is that Vos should do more to respond to former President Donald Trump’s unfounded allegations of election fraud in 2020.

Primary challengers, such as the one facing Vos next Tuesday, have been successfully targeting incumbent state legislators across the country, with Republicans bearing the brunt of the brunt.

With more than half of the state legislative primaries completed, Republican incumbents are losing at nearly twice the rate of the previous decade, according to data compiled for The Associated Press by the election tracking organization Ballotpedia. The primary loss rate for Democratic state lawmakers is similar to previous elections.

On Tuesday, Trump-backed candidates defeated incumbent state senators in Arizona and Michigan, and a conservative challenger defeated the assistant majority leader of the Missouri Senate. Though not an incumbent, Arizona House Speaker Rusty Bowers lost a bid for state Senate after being chastised for refusing to assist Trump’s efforts to overturn the 2020 election.

Republican lawmakers are frequently defeated by challengers who portray themselves as more conservative on issues such as election integrity, transgender policies, school instruction, and other contentious issues.

Christiansen, who considers himself “very conservative,” faced multiple opponents and did not advance to a runoff. That came after he voted against overriding Republican Gov. Asa Hutchinson’s veto of legislation that would make Arkansas the first state to prohibit gender-confirming treatments for those under the age of 18. Christiansen argued that the legislation was unconstitutional because it made no exception for youths who were already undergoing such treatments.

Vos, the Wisconsin Assembly speaker since 2013, has come under fire for failing to pursue a resolution decertifying Democrat Joe Biden’s victory in the state. Trump endorsed his Republican opponent, Adam Steen, saying in the 2020 election, “Vos refused to do anything to right the wrongs that were done.”

Prior to Tuesday, twenty-seven states had held legislative primaries or conventions. At least 110 Republican incumbents and 33 Democratic incumbents were defeated. The Republican loss rate of 7.1 percent is significantly higher than the Democratic rate of 2.8 percent. It also outperforms the 3.6 percent average Republican incumbent loss rate in those states over the previous decade, as well as the 4.4 percent Republican loss rate in those states during the last redistricting election cycle in 2012.

Idaho voters led the way in unseating Republican incumbents, defeating 18 GOP lawmakers — or 30% of those running for reelection — despite electing GOP Gov. Brad Little over a Trump-backed challenger who claimed he wasn’t conservative enough. Three lawmakers from Kootenai County in northern Idaho were among the losers, where a local Republican committee recommended conservative challengers against some incumbents after a lengthy vetting process.

Illinois state Rep. David Welter, one of nine Republican lawmakers expelled from the chamber in February for refusing to follow COVID-19 protocols and wearing masks, lost his primary in June to a challenger who claimed Welter wasn’t conservative enough. Welter’s votes for the Equal Rights Amendment and a construction bill that included a gas tax increase, among other things, were criticized by challenger Jed Davis.

Davis also slammed Welter’s ties to Illinois Rep. Adam Kinzinger, who became a GOP outcast after voting to impeach Trump and serving on the Democratic-led House panel investigating the Jan. 6, 2021, attack on the United States Capitol. Welter previously worked for Kinzinger’s campaign and has received $32,500 in contributions from Kinzinger-related committees since 2021.

According to an analysis in a forthcoming book by Saint Louis University political scientist Steven Rogers, when legislative districts tilt further right or left, incumbents are more likely to face challengers, and candidates who take more extreme positions are more likely to win.

Wisconsin’s state legislative districts were among the most pro-Republican in the country over the last decade, with only minor changes before this year’s election.

According to Anthony Chergosky, a political scientist at the University of Wisconsin-La Crosse, the majority of the challengers are likely to lose. They could, however, leave their mark by pushing incumbents further to the right in order to appease the GOP base that votes in primaries.