CHICAGO — The most powerful lawmaker in Wisconsin is walking away from his job. The most powerful legislators in North Carolina and Utah lost bids for a new term. Both top lawmakers in Vermont are retiring.

The exodus of state legislative leaders this year is widespread: Nearly a third of the nation’s House speakers, Senate presidents and majority leaders are retiring, running for other office or have already lost their primary bids.

And that turnover comes before November’s midterm elections, when changes in partisan control of legislative chambers may relegate more leaders to the minority, or out of office altogether.

In interviews, legislators attributed the unusually high number of exits to a handful of causes: Voter anger at longtime incumbents they have sent packing, an increase in the partisanship that infects the federal government trickling down into the states, and just plain burnout after a long time on the job.

“The job is changing. It’s becoming a little bit more challenging. There are more and more demands. If you’ve served for a while and you’ve given it your all, maybe it’s time to move on,” Utah Senate President Pro Tem Wayne Harper, a Republican who isn’t up for re-election until 2028, said in an interview. “There are more and more meetings, there are more and more constituent services, and to try to maintain a full-time job with a part-time legislature, that is a tricky balance.”

In June, Utah Senate President Stuart Adams, a fellow Republican, lost his bid for re-election in the Republican primary. That came a month after North Carolina Senate President Phil Berger, also a Republican, narrowly lost his own primary.

President Trump’s ire has cost some legislators their leadership posts. In Indiana, where some Senate Republicans refused a presidential edict to redraw congressional district lines, Senate President Rodric Bray and Majority Leader Chris Garten both said they would step down from their roles while remaining in the Senate. Majority Caucus Chair Travis Holdman was one of six Republicans who voted against the redistricting plan who lost their seats in the May primary.

“The American electorate has been in an anti-incumbent mode for a decade now, with every election being a ‘change’ election at the national level,” said Thad Kousser, a political scientist at the University of California San Diego who studies legislatures. “We do see the impact of the revolt against those in power in some primaries, where voters can voice their discontent without crossing the party divide.”

Legislative leaders in Alaska, Colorado, Connecticut, Delaware, Mississippi, Nevada, New York, Tennessee and Washington have all said they will retire this year. In Vermont, Alaska and Wisconsin, leaders in both chambers are calling it quits.

Wisconsin Assembly Speaker Robin Vos, a Republican who has served 22 years in office and 14 as speaker, said the public’s antipathy toward elected officials is changing the nature of what it means to be a veteran lawmaker.

“The idea of longtime legislators is going away. If you think of the private sector, people change jobs pretty rapidly now,” Vos said. “The idea of having people do the job of an elected official for a shorter time is probably going to happen naturally.”

Ten legislative leaders are seeking to use their posts as a stepping stone to higher office. Kansas Senate President Ty Masterson, Minnesota House Speaker Lisa Demuth and South Dakota House Speaker Jon Hansen all launched Republican campaigns for governor this year; Hansen lost the GOP primary.

Ohio Senate President Rob McColley is running for lieutenant governor. Kansas House Speaker Dan Hawkins is running for insurance commissioner, while Arizona Senate President Warren Petersen and Nevada Senate Majority Leader Nicole Cannizzaro, a Democrat, are running for attorney general.

Alaska House Speaker Bryce Edgmon, an independent, and Wyoming House Speaker Chip Neiman, a Republican, are both running for seats in the state Senate.

Vos said the exodus of legislative leaders would come at a cost to legislative institutions.

“I think that really weakens the institution, because governors are there for 4, 8, 12, 16 years and people accept that. Somehow if you’re a legislative leader and you’re there for four years you’ve been around too long,” Vos said.

“I think that we need to figure a way to balance both of those out so we have people with experience and people with new ideas, but we don’t want to cycle through people like a business would.”